An optical device includes: an incident optical system; an analysis optical system; and a length measurement optical system. The incident optical system includes a laser light source, and an incident light dividing element that divides the laser light. The analysis optical system includes a first light dividing element that divides the first divided light and then mixes the light, a first mirror that adds a first modulation signal to the one first divided light by movement and reflection, a second mirror, and a first light receiving element that receives the first divided light including a sample-derived signal and the first modulation signal. The length measurement optical system includes a second light dividing element that divides the second divided light and then mixes the light, an optical feedback unit that feeds back the one second divided light to the second light dividing element, and a second light receiving element that receives the second divided light including a displacement signal generated by the first mirror.

A distance measuring device measures a distance to a target object with high accuracy by reducing stray light in a probe tip end section.

In the distance measuring device, the probe tip end section has an optical path switching element that switches an optical path of measurement light incident from the optical element, at a tip end of the probe tip end section. A material of at least a part of the probe tip end section provided at a position opposite to a fifth surface absorbs the measurement light.

Provided is a pupil image measuring device including a light source configured to generate and output a light, a stage on which a measurement target is loaded, an optical system configured to transmit the light output from the light source, to the measurement target, a detector configured to detect a light reflected from the measurement target, and a spatial light distribution controller configured to adjust an intensity or amount of the light output from the light source or the reflected light, for each space of a plurality of spaces of the spatial light distribution controller, wherein the spatial light distribution controller is disposed on a pupil plane.

A 3D surface map of a workpiece is determined using an interferometric quantitative phase imaging technique. The workpiece includes a transparent thin film or layers stack. The 3D surface map is corrected based on a thickness and a refractive index of the transparent thin film or layers stack. This technique can be used with an inspection system configured to perform an interferometric quantitative phase imaging.

Disclosed is a method and corresponding apparatus for determining an absolute optical distance between two reflecting surfaces that make up an interferometric cavity, the method comprising: moving an illumination spot in a back focal plane of an interferometer along a trajectory that has a nonzero radial component relative to an optical axis to cause different radial positions for the illumination spot along the trajectory while synchronously acquiring images of interferograms of the interferometric cavity; and using one or more electronic processors to analyze the images to determine a functional dependence of an optical path difference (OPD) for the interferometric cavity versus radial position for the illumination spot and extract the absolute optical distance between the two reflecting surfaces based on the determined functional dependence.

Disclosed is a method and corresponding apparatus for determining an absolute optical distance between two reflecting surfaces that make up an interferometric cavity, the method comprising: moving an illumination spot in a back focal plane of an interferometer along a trajectory that has a nonzero radial component relative to an optical axis to cause different radial positions for the illumination spot along the trajectory while synchronously acquiring images of interferograms of the interferometric cavity; and using one or more electronic processors to analyze the images to determine a functional dependence of an optical path difference (OPD) for the interferometric cavity versus radial position for the illumination spot and extract the absolute optical distance between the two reflecting surfaces based on the determined functional dependence.

A method for measuring at least one cross-sectional dimension of a cylindrical hollow body having a wall surrounding a lumen, a longitudinal axis, an inner surface and an outer surface includes: directing a light beam along a travel path from an interferometric device towards the outer surface, such that at least intermittently at least a portion of the light beam hits the outer surface of the hollow body; receiving a portion of light reflected at the outer surface and receiving a portion of light reflected at the inner surface along the travel path at the interferometric device; obtaining at least one cross-sectional dimension of the hollow body based on an interferometric measurement of the portion of light reflected at the outer surface and/or the portion of light reflected at the inner surface; and varying an orientation of the travel path of the light beam towards the hollow body.

A weighing device includes: a support having a placement surface on which an object to be measured is to be placed, the placement surface being displaced according to a mass of the object to be measured; a mirror disposed on the support; a laser interferometer configured to detect, using a laser beam, a change in optical path length to the mirror due to the displacement of the placement surface; and a controller configured to calculate a weight or a mass of the object to be measured based on the detected change in optical path length, in which the laser interferometer includes a laser light source configured to emit the laser beam, and a optical modulator including a vibrator and configured to modulate a frequency of the laser beam using a vibration of the vibrator.

The system includes a light source that emits partially coherent or coherent light split into a reference beam and an object beam and a stage that supports a workpiece in a path of the object beam, that is transmitted through the workpiece. The workpiece includes a vertical interconnect access (VIA) extending from a first side to a second side of the workpiece. A first beam splitter combines the reference beam with the object beam transmitted through the workpiece into a combined beam, and a camera detects the combined beam received. A processor generates an interference image of the workpiece based on the combined beam, determines amplitude and phase information of the object beam based on the interference image, generates a plurality of depth images of the workpiece based on the amplitude and phase information, and determines a critical dimension (CD) of the VIA based on the plurality of depth images.

Provided are a detection system, compensation method and computer-readable recording medium applicable to semiconductor surface morphology to provide feature information corresponding to spectral signals to a neural network model and provide feature information corresponding to spectral signals, a detected height, and an actual height actually measured to another neural network model. The combinational neural network models thus trained and built can generate a compensation value for a to-correct height corresponding to a to-correct spectral signal having variability. The compensation value provides required compensation for height information to not only enhance the precision of the detection of semiconductor surface morphology but also enhance the reliability of the detection system.