A non-contact-type apparatus for measuring wafer thickness includes a monolithic-type wavelength sweeping semiconductor laser light source having a laser source, a laser control unit that controls the laser source, and a processor to control the laser source to oscillate laser light having a wavelength that changes with a setting profile relative to time; an optical system that guides and emits the laser light onto a wafer; a detection unit that detects an interference light signal of reflected light; an A/D converter that converts the interference light signal detected by the detection unit into a digital signal; and a calculation unit that calculates a thickness of the wafer by analyzing the digital signal from the A/D converter. The processor causes the laser control unit to operate with a clock signal, and to oscillate laser light that performs wavelength-sweeping with the setting profile relative to the time, from the laser source. The A/D converts the interference light signal by generating a sampling clock in synchronization with the clock signal or directly using the clock signal as a sampling clock.

The present invention is a method for measuring the varnish film thickness of a printed article by obtaining the film thickness of varnish on a sheet (1) on which a pattern is printed on a base thereof with ink and the pattern is coated with the varnish, wherein a metal foil (1c) having a smooth surface is attached to the base of the sheet (1), and the film thickness of the varnish coated directly over the metal foil (1c) is detected with a spectral interference-type film thickness meter (81) so as to determine whether the film thickness of the varnish is acceptable or not on the basis of the results detected by the spectral interference-type film thickness meter (81).

The magnetic tape includes a non-magnetic support; and a magnetic layer in which the magnetic layer has a timing-based servo pattern, an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference between a value L.sub.99.9 of a cumulative distribution function of 99.9% and a value L.sub.0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less, and a difference between a spacing S.sub.after measured on a surface of the magnetic layer by an optical interferometry after methyl-ethyl-ketone cleaning and a spacing S.sub.before measured on the surface of the magnetic layer by an optical interferometry before methyl-ethyl-ketone cleaning is greater than 0 nm and 15.0 nm or less.

A method for contactless and non-destructive determination of the layer thicknesses of lacquer layers of vehicle parts is disclosed. In addition, the invention relates to a device to determine and measure the lacquer layers of vehicle part, the device constructed for performing optical coherence tomography and includes at least one radiation source for providing electromagnetic radiation and the electromagnetic radiation provides a wavelength (λ) of 100 nm-15.Math.10.sup.3 nm and in particular 380 nm to 800 nm.

Disclosed herein is an endpoint detection having an optical bundle configured to emit light through a ceiling of a processing chamber. The optical bundle has a plurality of fibers configured to transmit the light from a light source towards a substrate and is configured to receive light reflected from the substrate. The plurality of fibers include a first emitting fiber and a first receiving fiber. The first receiving fiber is radially disposed at a pairing angle from the first emitting fiber, and is configured to receive light emitted from the first emitting fiber. The plurality of fibers further include a second emitting fiber and a second receiving fiber. The second receiving fiber is radially disposed at the pairing angle from the second emitting fiber. The second receiving fiber is configured to receive light originating from the second emitting fiber. The pairing angle is between about 175 degrees and 185 degrees.

A height detection apparatus successively changes the brightness of white light from a first level to a second level in accordance with a position of a Z stage and captures an image of interference light while moving a two-beam interference objective lens relative to a paste film in an optical axis direction, detects, as a focus position, a position of the Z stage where the intensity of interference light is highest in a period during which the brightness of white light is set to the first or second level, for each pixel of the captured image, and obtains the height of the paste film based on a detection result.

A method for measuring interfaces of an optical element, forming part of a plurality of similar elements including at least one reference optical element, the method implemented by a device, the method including: relative positioning of each reference optical element and the measurement beam, to allow a measurement of interfaces of each reference optical element; acquisition of a reference image, of each reference element; positioning of the measured optical element to allow acquisition of a measurement image, of the optical element to be measured; determining a difference of position in a field of view of the measured element with respect to each reference optical element, based on the reference and measurement images; adjusting the position of the measured optical element in the field of view to cancel the difference of position; and measuring the interfaces of the measured optical element by the measurement beam.

A spectroscopic measuring apparatus and method are provided. The apparatus includes a first light source, object, microlens, and imaging lenses, an optical fiber, a spectrometer and a position controller. The object lens to allows light from the first light source to be incident on a stage configured to support a measurement object. The microlens is disposed between the object lens and the stage. The imaging lens images light reflected from the measurement object. The optical fiber has an input terminal disposed on a first image plane of the imaging lens. The spectrometer is disposed at an output terminal of the optical fiber. The position controller controls positions of the object lens, the microlens, and the optical fiber, and adjusts the position of the object lens so that a focus of the object lens is positioned at a virtual image position of a virtual image generated by the microlens.

A measuring method includes storing thickness data of each of chips held on a holding surface of a holding table, the thickness data being obtained by measurement of thicknesses of portions of the chip at a plurality of measurement points and representing the thicknesses measured at the measurement points in association with positions of the measurement points in a predetermined plane corresponding to a reverse side of the wafer, storing positions of central lines of dividing grooves in the predetermined plane in captured images of reverse sides of the chips, setting, in a periphery of each of the chips, a thickness data unreferencing zone including measurement points where the thickness data will not be referenced in calculating the thickness of the chip, and calculating, for each of the chips, an average value of thicknesses at the measurement points except for the measurement points included in the thickness data unreferencing zone.

A two-degree-of-freedom heterodyne grating interferometry measurement system, comprising: a single-frequency laser device for emitting a single-frequency laser, and the single-frequency laser can be split into a beam of reference light and a beam of measurement light; an interferometer mirror group and a measurement grating for forming a reference interference signal and a measurement interference signal from the reference light and the measurement light; and a receiving optical fiber for receiving the reference interference signal and the measurement interference signal, wherein a core diameter of the receiving optical fiber is smaller than a width of an interference fringe of the reference interference signal and the measurement interference signal, so that the receiving optical fiber receives a part of the reference interference signal and the measurement interference signal. The measurement system has advantages of insensitivity to grating rotation angle error, small volume, light weight, and a facilitating arrangement.