Abstract: The present invention relates to a non-contact, non-destructive measuring apparatus that measures thickness profile and refractive index distribution of a single or multiple layers of thin films by means of the principle of reflectometry. According to the present invention, by employing more than one narrow band-pass optical filters and a two-dimensional array of CCD sensors, and by finding an optimal solution for the nonlinear functional relationship between the thickness of said thin film or thin films and the corresponding refractive indexes by using an iterative numerical computation method, said apparatus simultaneously measures local area-wise thickness profile and refractive index distribution among others of said a single layer or multiple layers of thin films on a substrate.

Abstract: A method for simultaneous measuring a thickness of a liquid crystal layer and an average refractive index of the said liquid crystal in sealed liquid crystal cell is disclosed. The method is based on analysis of spectral positions of maxima and minima of interference oscillations, their magnitudes and their envelope in the spectrum of light mirrored by the liquid crystal cell at several different angles-of-incidence. The method is applicable to cells filled with different liquid crystals including cholesterics and smectics.

Abstract: An anodizing system for forming a anodized coating on at least a portion of a substrate thereby creating an anodized substrate is disclosed. The anodizing system includes a bath, a coating thickness monitor, at least one probe and at least one controller. The coating thickness monitor includes at least one radiation source directed at at least a portion of the anodized substrate; at least one probe for capturing at least a portion of the radiation reflected and refracted by the anodized coating on the anodized substrate, the captured radiation being at least a portion of the radiation directed the anodized substrate from the radiation source; and at least one detector in communication with the at least one probe, the at least one detector capable of processing the captured radiation to allow a determination of at least the thickness.

Abstract: With technical surfaces, in particular in semiconductor manufacture, it is a regular requirement to determine the reflection coefficient. For this purpose, a model spectrum of an object of a plurality of wavelengths and a defined number of intermediate points is calculated. To increase the calculating speed, the defined number of intermediate points is calculated prior to the execution of the calculation.

Abstract: The disclosure includes a system, device, apparatus and programmed medium of measuring thickness of an optical disc by using an interference effect of the optical disc layer. Such a system can include: a spectroscope to separate light, reflected from a surface of an optical disc, into constituent frequencies thereof; an optical intensity measuring unit to measure intensities of the constituent frequencies, respectively, as a first spectrum of data; and a processor to do at least the following, convert the first spectrum data into a second spectrum of values that exhibits variation as a function wavelength and refractive index, transform the second spectrum using a Fast Fourier Transform, and detect a thickness of one or more of the spacer layer and the cover layer, respectively, based upon the transformed spectrum. The disclosed technologies have advantages for high precisely measuring thickness of an optical disc.

Abstract: A method of determining the rate of change of optical thickness of a thin-film during deposition comprising the steps of illuminating the thin-film (5) with electromagnetic radiation (3) having a range of wavelengths, measuring the transmission spectrum (6,7) of the thin-film (5) at least twice during the deposition process to determine the wavelength ?t or turning points in the transmission spectrum, and using the measurements to determine the rate to change of optical thickness of the thin-film as a function of time. The method further comprises the steps of predicting a time T in the growth process at which the wavelength ?t of the turning point in the transmission spectrum of the thin-film will be substantially equal to the wavelength ?d of the turning point in the transmission spectrum of thin-film at its optical design thickness, and interrupting the growth process such that growth ceases at time T.

Abstract: A target detection apparatus is provided which can detect and quantitatively measure various detection targets such as pathogens. For this purpose, the apparatus comprises an optical irradiation unit which irradiates light; an optical interference unit which can interact with the detection target, interferes with the light irradiated from the optical irradiation unit and radiates it as interference light and change the wavelength of the interference light after interaction with the detection target; and an wavelength change detecting unit which detects the wavelength change of the interference light radiated by the optical interference unit. The wavelength change detecting unit preferably measures spectrums before and after wavelength change of the interference light, and their differential spectrum. Also provided is a target detection substrate comprising a film-like material on a substrate which, when interacting with a detection target, changes the wavelength of the interference light.

Abstract: A method for measuring the cavity length of a remote sensing interferometer by locally replicating the state of the remote sensing interferometer by way of a local interferometer. The local interferometer is produced by micro-electromechanical micro machining techniques, thus obtaining a highly accurate and reliable fiber optic sensing at a cost comparable to electronic sensing devices.

Abstract: A method and device for determining the topography of a thin film having a front surface and a back surface. The method comprises: irradiating the film with an incident coherent or partially coherent light beam so as to get two reflected beams, the first reflected beam being reflected from the front surface of the film, and the second beam being reflected from the back surface of the film; creating an interferometric image from a united beam comprising the two reflected beams and a reference beam, the reference beam originating from the incident beam, and made to be substantially parallel to the two reflected beams. The reference beam acquires a phase shift. The interferometric image is created the interference between a combined beam comprising the reference beam and the second reflected beam, and the first reflected beam, thus acquiring information on the topography of the film, that cannot be acquired using the two reflected beams alone.

Abstract: A spin etcher with a thickness measuring system includes a rotatable spin head, etchant supply means, and etchant supply controller. A substrate is mounted upon the spin head. The etchant supply means is disposed over the substrate, and sprays an etchant onto the substrate. The etchant supply controller controls the etchant supply. The spin etcher further includes a main controller for transferring an etchant supply stop signal to the thickness measuring system and the etchant supply controller. The thickness measuring system allows a light to impinge on a surface of the substrate, and analyzes an interference signal of the light reflected from the substrate to measure a thickness of a thin film. The main controller compares a result measured by the thickness measuring system with a reference value, and transfers the etchant supply stop signal to the etchant supply controller before the measured result reaches the reference value.

Abstract: A method of measuring thickness of an optical disc by using an interference effect of the optical disc layer is disclosed. The method includes detecting an intensity of a reflective light according to a wavelength of a light as spectrum data for each wavelength, converting the detected spectrum data for each wavelength into a spectrum value as a function of a wavelength that a refractive index is reflected, and detecting a position where the intensity of the reflective light has a peak as a thickness of a spacer layer and a cover layer respectively by converting the converted value into a length of an interference area for representing a layer thickness of the optical disc by the Fast Fourier Transform. The disclosed method has advantages for high precisely measuring thickness of an optical disc.

Abstract: Standard patterns of differential values of interference light that correspond to a predetermined step height of the first material being processed and standard patterns of differential values of interference light that correspond to a predetermined remaining mask layer thickness of the material are set. These standard patterns use wavelengths as parameters. Then, the intensities of interference light of multiple wavelengths are measured for a second material that has the same structure as the first material. Actual patterns with wavelength as parameter are determined from differential values of the measured interference light intensities. Based on the standard patterns and the actual patterns of the differential values, the step height and the remaining mask layer thickness of the second material are determined.

Abstract: A manufacturing method and manufacturing device for high-precision thin film devices is disclosed, whereby the film thickness and film thickness distribution of a transparent film is measured to a high degree of accuracy during a CMP process without being affected by the film thickness distribution between LSI regions or within the semiconductor wafer surface generated by CMP processing. Film thickness is measured by specifying relatively level measurement regions, according to a characteristic quantity of the spectral waveform of the reflected light from the transparent film, such as the reflection intensity, frequency spectrum intensity, or the like, thereby permitting highly accurate control of film thickness. The leveling process in CMP processing can be optimized on the basis of the film thickness distribution. The film deposition conditions in the film deposition stage and the etching conditions in the etching stage can also be optimized.

Abstract: Two threshold parameters are used to identify the intensity modulation peaks corresponding to the interfaces of the two sides of a thin film with the adjacent media. The first parameter is used to distinguish modulation data from noise and is set on the basis of actual background noise data measured during the interferometric scan. The second parameter is used to separate actual contrast data from signals of relatively high modulation that satisfy the first parameter but do not in fact result from interference fringes. Data that satisfy both parameters are considered valid modulation data and the peak of each modulation envelope is then calculated using conventional means. The thickness of the film at each pixel is obtained by dividing the scanning distance corresponding to the two peaks by the group index of refraction of the film material.

Abstract: A system and method for analyzing the characteristics of a thin film is provided. The current invention extends the capability of IR sensors to measure thin films through configuring a plurality of detection channels with appropriately chosen filters. With the multichannel infrared sensor, the characteristic signature of interference fringes can be detected simultaneously with, or instead, of absorption-based measurements.

Abstract: A method and apparatus for measuring the optical thickness and absolute physical thickness of an optically transparent object utilizes a reflective interferometric process. A broadband optical signal is directed toward the object to be measured, and a pair of signals reflected off of the object are processed to determine the optical thickness of the object. When used with an optical fiber preform, the technique can be used to measure the outer diameter of the preform and control the drawing process. If the index of refraction of optically transparent object is known, the absolute physical thickness can also be determined.

Abstract: A frequency-scanning interferometer is modified to include a diffuse reference surface. An illuminating system produces an expanding measuring beam, portions of which reflect from a test object surface and the diffuse reference surface on converging paths to an imaging system. Interference patterns between overlapping images of the object and reference surfaces are generated at a plurality of frequencies for measuring the object surface with respect to the reference surface.

Abstract: An optical metrology system is provided with a data analysis method to determine the elastic moduli of optically transparent dielectric films such as silicon dioxide, other carbon doped oxides over metal or semiconductor substrates. An index of refraction is measured by an ellipsometer and a wavelength of a laser beam is measured using a laser spectrometer. The angle of refraction is determined by directing a light pulse focused onto a wafer surface, measuring a first set of x1, y1, and z1 coordinates, moving the wafer in the z direction, directing the light pulse onto the wafer surface and measuring a second set of x2, y2 and z2 coordinates, using the coordinates to calculate an angle of incidence, calculating an angle of refraction from the calculated angle of incidence, obtaining a sound velocity v, from the calculated angle of refraction and using the determined sound velocity v, to calculate a bulk modulus.

Abstract: A method of determining a parameter of interest during fabrication of a patterned substrate includes illuminating at least a portion of the patterned substrate with a normal incident light beam, obtaining a measured net reflectance spectrum of the portion of the patterned substrate from a normal reflected light beam, calculating a modeled net reflectance spectrum of the portion of the patterned substrate, and determining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum. The modeled net reflectance spectrum is calculated as a weighted incoherent sum of reflectances from n?1 different regions constituting the portion of the patterned substrate, wherein the reflectance of each of the n different regions is a weighted coherent sum of reflected fields from k?1 laterally-distinct areas constituting the region.

Abstract: The present invention provides a method of measuring the thickness of a thin film or thin layer by a spectroscopic measurement, which is applicable to the measurement of a multiple layered film whose layers have different refractive indices. According to the method, an interference light from the film is measured to create a measured spectrum. The waveform of the measured spectrum can be approximately represented by a linear sum of base spectrums. Accordingly, various constructed spectrums are created using base spectrums each having a cycle interval as a parameter. Then, the constructed spectrum that minimizes the square error against the measured spectrum is identified. The least square error is calculated for each of predetermined cycle intervals. A graph is drawn to represent the relation between the least square error and the cycle interval. The correspondence between the layers and the plural minimum points of the least square error appearing on the graph is determined.

Abstract: A method is disclosed for contactless determination of product characteristics, particularly in continuous or discontinuous fabrication of layer systems formed of a plurality of layers with different optical characteristics. The measuring apparatus and measurement methods for determining the characteristics of one of the respective layers are predetermined depending on the optical characteristics of this layer and depending on the optical characteristics of layers situated above it in the measuring direction. In a measuring device for this purpose, a plurality of detectors are provided for wavelength regions directly adjoining one another. The detectors and the signal processing device are constructed such that the light coming from the measurement surface with wavelengths of 200 nm to more than 2400 nm is evaluated in its entirety.

Abstract: Standard patterns of differential values of interference light that correspond to a predetermined step height of the first material being processed and standard patterns of differential values of interference light that correspond to a predetermined remaining mask layer thickness of the material are set. These standard patterns use wavelengths as parameters. Then, the intensities of interference light of multiple wavelengths are measured for a second material that has the same structure as the first material. Actual patterns with wavelength as parameter are determined from differential values of the measured interference light intensities. Based on the standard patterns and the actual patterns of the differential values, the step height and the remaining mask layer thickness of the second material are determined.

Abstract: A process recipe is controlled by processing reflection interference light on the surface of a wafer with a signal and etching is carried out by suppressing an increase in the surface roughness of the wafer during etching. That is, a dry etching method for use in a dry etching system comprising means of treating a sample by generating plasma in a vacuum process chamber and monitor means of monitoring the reflection interference light of the sample to be treated, the method comprising the step of detecting the spectrum of reflection interference light on the surface of the sample to be treated, the step of obtaining a residual from curve fit between a theoretical value estimated from the film reflection model of the surface of the wafer and the spectrum of reflection interference light, and the step of judging whether the residual from the curve fit falls within a predetermined value.

Abstract: A monochromatic light is cast on a thin layer, and the intensity of the reflected light which is an interference light of the lights reflected by the front surface and back surface of the layer. A spectrum (a measured spectrum) is obtained from the measured intensity by scanning the wavenumber of the monochromatic light. On the other hand, a constructed spectrum is created based on an assumed thickness using a predetermined function. Then an error between the measured spectrum and the constructed spectrum is calculated. The value of the error is plotted against the assumed thickness, and the point at which the error is minimum is detected. The assumed thickness at the error-minimum point is determined as the thickness of the layer.

Abstract: The invention concerns a method for the determination of layer thickness ranges of layers of a specimen, in which the reflection spectrum of the specimen is measured in a specified wavelength range and then smoothed, the number of extremes in the smoothed reflection spectrum is determined, and the determination of the layer thickness ranges is accomplished by comparison with the number of extremes in the modeled reflection spectra, such that for each layer the thickness in that layer is varied in steps having a predetermined increment, and a reflection spectrum is modeled. In a method of this kind, the wavelength range and the increments are specified in self-consistent fashion using a sensitivity criterion.

Abstract: An end point detection system may compare a production image developed during processing of production semiconductor wafer with a reference image. The reference image is representative of a desired state of processing of the production semiconductor wafer. The reference image is determined by processing a reference semiconductor wafer. The reference semiconductor wafer may be part of a wafer group of similar wafers that includes the production semiconductor wafer. The end point detection system may dynamically develop the production image during processing of the production semiconductor wafer. Indication may be provided by the end point detection system when the reference image and the production image are substantially similar.

Abstract: Standard patterns of differential values of interference light that correspond to a predetermined step height of the first material being processed and standard patterns of differential values of interference light that correspond to a predetermined remaining mask layer thickness of the material are set. These standard patterns use wavelengths as parameters. Then, the intensities of interference light of multiple wavelengths are measured for a second material that has the same structure as the first material. Actual patterns with wavelength as parameter are determined from differential values of the measured interference light intensities. Based on the standard patterns and the actual patterns of the differential values, the step height and the remaining mask layer thickness of the second material are determined.

Abstract: A high-resolution and high-speed film thickness and thickness uniformity measurement method is disclosed in this invention. The disclosed method includes a step a) of measuring a film thickness at a single point on the top surface of the substrate using an interferometry with a measuring light beam having a range of wavelengths. The method further includes a step b) of selecting an optimal wavelength from the range of wavelengths applied for measuring the film thickness at the single point. The method further includes a step c) of measuring reflection intensities by scanning over a plurality of points with a measuring light beam of the optimal wavelength over the top surface of the substrate. The method further includes a step d) of calculating a film thickness at the plurality of points applying the optimal-wavelength reflection intensities at the plurality of points over the top surface of the substrate.

Abstract: A method and system using spectral interference of light from plasma emissions collected at near grazing incidence to in-situ monitor and control the film thickness of a non-opaque film. Embodiments of this invention are particularly useful to all substrate processing chambers equipped to form an in-situ plasma within the chamber and which are used to deposit or etch non-opaque films. One embodiment of the method of the present invention forms a plasma within a substrate processing chamber to deposit a non-opaque film on a wafer substrate within the chamber. During the plasma deposition process, a plurality of wavelengths of radiation including those reflected from the top and bottom layer of the film being deposited upon a wafer surface are collected through an existing viewport, and conveyed to a spectrometer for measurements via an optical fiber attached near this viewport. These measurements are analyzed to determine the film's thickness.

Abstract: A method and system are presented for use in controlling a process of material removal from the surface of a patterned structure, by measuring at least one of residue, erosion, dishing and corrosion effects in the structure induced by this process. The structure is imaged utilizing phase modulation of light reflected from the structure, and a phase map of the structure is thereby obtained. This phase map is analyzed and data indicative of light reflective properties of layer stacks of the structure is utilized to determine a phase difference between light reflected from a selected measured site and at least one reference site spaced-apart from the selected site. The phase difference is thus indicative of the measured effect.

Abstract: A method for optically detecting a trench depth includes detecting a first maxima in an intensity of multi-wavelength light. A portion of the multi-wavelength light is reflected from a top trench surface. A second maxima in an intensity of multi-wavelength light is also detected. A portion of the multi-wavelength light is reflected from a bottom trench surface. A maxima peak separation between the first maxima and the second maxima is determined. The trench depth corresponds to the maxima peak separation.

Abstract: A method of measuring thickness of an optical disc by using an interference effect of the optical disc layer is disclosed. The method includes detecting an intensity of a reflective light according to a wavelength of a light as spectrum data for each wavelength, converting the detected spectrum data for each wavelength into a spectrum value as a function of a wavelength that a refractive index is reflected, and detecting a position where the intensity of the reflective light has a peak as a thickness of a spacer layer and a cover layer respectively by converting the converted value into a length of an interference area for representing a layer thickness of the optical disc by the Fast Fourier Transform. The disclosed method has advantages for high precisely measuring thickness of an optical disc.

Abstract: The present invention relates to a non-contact, non-destructive measuring apparatus that measures thickness profile and refractive index distribution of a single or multiple layers of thin films by means of the principle of reflectometry. According to the present invention, by employing more than one narrow band-pass optical filters and a two-dimensional array of CCD sensors, and by finding an optimal solution for the nonlinear functional relationship between the thickness of said thin film or thin films and the corresponding refractive indexes by using an iterative numerical computation method, said apparatus simultaneously measures local area-wise thickness profile and refractive index distribution among others of said a single layer or multiple layers of thin films on a substrate.

Abstract: A method and apparatus for determination of layer thicknesses and optical parameters of a number of layers of a specimen, in which the reflectance spectrum of the specimen is measured and then smoothed, and a modeled reflectance spectrum is adapted to the measured one by means of an optimization criterion so as thereby to determine the layer thickness. The optimization criterion is determined by the totality of the absolute values of the wavelength differences of all pairs of wavelengths, a pair of wavelengths being constituted by those wavelengths that respectively correspond to a selected extreme in the measured reflectance spectrum characterized by an index counting the extremes in ascending or descending order, and a selected extreme in the modeled reflectance spectrum having the same index.

Abstract: There are provided a thickness-measuring method and apparatus capable of measuring thicknesses of respective layers of a multilayer thin film used in functional resin films or information electronic materials at a still higher accuracy and instantaneously, which are also applicable to a sample in production line non-destruct. In the thickness-measuring method for the multilayer thin film, a reflected or transmitted light obtained by irradiating a white light onto a sample (7) having the multilayer thin film is spectrally dispersed to obtain a spectrum thereof; and the obtained spectrum is transformed into a frequency signal which is then subjected to wavelet processing to remove components other than coherence signals from the frequency signal, and then the resultant signal is subjected to frequency analysis to detect the thicknesses of layers of the thin film.

Abstract: This invention aims to measure film thickness and film thickness distribution to high precision in a wide range of transparent films. As one example, in a CMP process, the film thickness of an outermost surface layer formed on a step pattern of an actual product can be measured so that high precision film thickness control can be performed. To achieve an increase of processing throughput, the film thickness of an optically transparent film formed on an actual device pattern is controlled to high precision by incorporating a film thickness measuring unit, which performs frequency analysis of a spectral distribution, in a polishing apparatus. As a result, an increase of processing throughput is realized.

Abstract: A method or apparatus for measuring lateral variations of a property such as thickness or refractive index of a transparent film on a semiconductor, in a region of repeated patterning comprises: illuminating over the patterned area with a beam of light of multiple wavelengths, the beam having dimensions to include repeated patterning; detecting the intensity of light reflected over the patterned area for each wavelength; producing a signal defining the variation of the intensity of the detected light as a function of the wavelength of the detected light; decomposing the signal into principal frequencies thereof, determining from the principal frequencies, values of the thickness etc. of the transparent film; and applying the values to repetitions within the repeated patterning.

Abstract: The invention relates to a method for measuring a required feature of a thin layer (4) used in a polishing process that is carried out by a polish head by producing a localized temperature rise on the surface of the layer (4) by focusing a short pump laser pulse (11) on the surface of the layer, as to generate a sound wave (13) that propagates into the layer; repeated measuring the surface reflection properties of the layer, by passing a probe laser pulse (21) and focusing it on the surface of the layer and by monitoring the portion of the probe laser pulse that is reflected (22) by the surface, as to detect a change in surface reflection properties caused by a boundary echo (32) that is a reflected part of the sound wave (13); measuring the elapsed time between the generation of the sound wave and the change in surface reflection properties; and calculating the required layer feature. Furthermore the invention relates to a measuring apparatus, which is able to perform the above-mentioned method.

Abstract: When a semiconductor wafer placed in a chamber and having films thereon is etched using plasma generated in the chamber, a change in the amount of lights with at least two wavelengths, obtained from the wafer surface during the processing, is detected. The time between the time at which the amount of a light with one of two wavelengths is maximized and the time at which the amount of a light with the other wavelength is minimized is compared with a predetermined value to determine the state of etching processing.

Abstract: A process recipe is controlled by processing reflection interference light on the surface of a wafer with a signal and etching is carried out by suppressing an increase in the surface roughness of the wafer during etching. That is, a dry etching method for use in a dry etching system comprising means of treating a sample by generating plasma in a vacuum process chamber and monitor means of monitoring the reflection interference light of the sample to be treated, the method comprising the step of detecting the spectrum of reflection interference light on the surface of the sample to be treated, the step of obtaining a residual from curve fit between a theoretical value estimated from the film reflection model of the surface of the wafer and the spectrum of reflection interference light, and the step of judging whether the residual from the curve fit falls within a predetermined value.

Abstract: The invention concerns a method for the determination of layer thickness ranges of layers of a specimen, in which the reflection spectrum of the specimen is measured in a specified wavelength range and then smoothed, the number of extremes in the smoothed reflection spectrum is determined, and the determination of the layer thickness ranges is accomplished by comparison with the number of extremes in the modeled reflection spectra, such that for each layer the thickness in that layer is varied in steps having a predetermined increment, and a reflection spectrum is modeled. In a method of this kind, the wavelength range and the increments are specified in self-consistent fashion using a sensitivity criterion.

Abstract: A method and an apparatus of inspecting the surface of a wafer, where two or more kinds of laser are switched or mixed to make the laser incident on the film-coated wafer by a same incident angle, in which inspection data regarding an inspection apparatus and film parameters regarding a film are stored in storage means of the inspection apparatus in an associated state with each other so as to obtain predetermined inspection conditions. When performing each measurement, an operator sets the film parameters of the wafer to be measured by setting means of the inspection apparatus. Thus, desired inspection conditions are automatically set in the inspection apparatus. The film parameters that the operator sets at each measurement are a film thickness and a film refraction index.

Abstract: Flatness and thickness variation information concerning transmissive plane-parallel test plates is obtained from a grazing incidence interferometer modified to distinguish between superimposed interference patterns containing both types of information. The grazing angle of the interferometer is varied, and unique modulation frequencies of local fringe intensities within the superimposed interference patterns are identified. The local fringe intensities attributable to the different interference patterns are distinguished by their respective modulation frequencies.

Abstract: This invention aims to measure film thickness and film thickness distribution to high precision in a wide range of transparent films. As one example, in a CMP process, the film thickness of an outermost surface layer formed on a step pattern of an actual product can be measured so that high precision film thickness control can be performed. To achieve an increase of processing throughput, the film thickness of an optically transparent film formed on an actual device pattern is controlled to high precision by incorporating a film thickness measuring unit, which performs frequency analysis of a spectral distribution, in a polishing apparatus. As a result, an increase of processing throughput is realized.

Abstract: The present invention provides a method and system for determining three-dimensional refractive gradient index distribution. The method and system of the present invention determine inhomogeneity data and calculate index of refraction changes in three-dimensions (3D). The method and system provide 3D modeling of an optical object or system that determines the three-dimensional distribution of the refractive index in the object. In one embodiment, the optical object is a blank. In different embodiments, the optical system is more than one blank. In alternative embodiments, the optical system can be a projection optics system that can include optical components such as lenses, filters, plates, and prisms. The present invention also provides a method for selecting a plurality of preferred optical elements to assemble a composite optical system with predetermined parameters.

Abstract: The present invention provides an apparatus comprising a wavelength variable light source for shifting a wavelength of light stepwise within a predetermined range and applying the light with the shifted wavelength onto a light transmissible object that is to be measured and is provided with a gap; a camera for taking an image of an interference fringe formed by the light transmitted by said object, correspondingly to each step of the shifted wavelength; an image memory for storing images taken by said camera; and means for obtaining a change in the intensity of the images taken by said camera, at each of predetermined positions of each image over said predetermined wavelength range; and means for determining gap values of a plurality of points of the gap based on the obtained changes in the intensity.

Abstract: It is an object of the invention to inspect defects of a film formed on a relatively rough surface of a substrate by the light interference method. A substrate on which a film is formed is irradiated with light of a longer wavelength than the surface roughness Rmax or Rz of the substrate to obtain interference fringes to inspect defects of the film formed on the substrate. Especially, it is preferable that when the surface roughness Rmax or Rz is 0.5 &mgr;m or more, the substrate is irradiated with light of a wavelength beyond a little longer wavelength than the surface roughness Rmax or Rz. The surface of the substrate is subjected to a cutting process. Specifically, it is possible to inspect defects of the electric charge generation layer, electric charge transport layer, or undercoat layer of an electrophotographic photoreceptor. This photoreceptor is mounted in a digital copier or printer. Further, monochromatic light is preferably applied.

Abstract: A method of determining a parameter of interest during fabrication of a patterned substrate includes illuminating at least a portion of the patterned substrate with a normal incident light beam, obtaining a measured net reflectance spectrum of the portion of the patterned substrate from a normal reflected light beam, calculating a modeled net reflectance spectrum of the portion of the patterned substrate, and determining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum. The modeled net reflectance spectrum is calculated as a weighted incoherent sum of reflectances from n≧1 different regions constituting the portion of the patterned substrate, wherein the reflectance of each of the n different regions is a weighted coherent sum of reflected fields from k≧1 laterally-distinct areas constituting the region.

Abstract: A method of determining a parameter of interest during processing of a patterned substrate includes obtaining a measured net reflectance spectrum resulting from illuminating at least a portion of the patterned substrate with a light beam having a broadband spectrum, calculating a modeled net reflectance spectrum as a weighted incoherent sum of reflectances from different regions constituting the portion of the patterned substrate, and determining a set of parameters that provides a close match between the measured net reflectance spectrum and the modeled net reflectance spectrum. For wavelengths below a selected transition wavelength, a first optical model is used to calculate the reflectance from each region as a weighted coherent sum of reflected fields from thin film stacks corresponding to laterally distinct areas constituting the region. For wavelengths above the transition wavelength, a second optical model based on effective medium approximation is used to calculate the reflectance from each region.

Abstract: The invention concerns a method for automatic determination of optical parameters of a layer stack, such as layer thicknesses, refractive indices, or absorption coefficients, by comparing an optical measured spectrum acquired from one location in the layer stack to an analysis spectrum calculated on the basis of specified optical parameter values, and optimizing the calculated analysis spectrum to the measured spectrum. It is proposed herein that the acquired measured spectrum be classified on the basis of curve shape parameters that characterize the measured spectrum and are determined therefrom, and that those curve shape parameters be compared to corresponding spectrum curve shape parameters calculated for known layer stacks in order to determine (initial) values or value ranges for the optical parameters to be identified, on the basis of which the analysis spectrum or spectra for comparison with the measured spectrum is/are calculated.