Abstract: In an operation of a pattern dimension measuring system comprising a stage, an electron gun part, electron lens systems for scanning electron beam on a sample and having a MOL mechanism thereto, a secondary electron detector for detecting secondary electrons and so forth emitted from the sample, and a host computer having a pattern dimension measuring part, the stage is moved at a constant velocity, the coordinates of the stage is measured by a laser interferometer in real time, the variation in working distance of the electron beam is measured in real time by the optical lever system from a focal length measuring part to be fed back to a stage control part and an objective lens. When a pattern serving as an object to be measured reaches a region capable of scanning, the electron beam is scanned in the best focus while moving the scanning start position of the electron beam in synchronism with the constant velocity movement of the stage, so that the SEM image thereof is acquired.

Abstract: A method for measuring a size of fine pattern wherein sizes of a plurality of fine patterns are measured using a scanning electron microscope is disclosed. The measuring method comprises the following procedures of obtaining a secondary electron image while scanning an electron beam on a fine pattern, determining whether or not the secondary electron image thus obtained meets a shape judgment criterion which has been set in advance, and, when the criterion is met as a result of determination processing, measuring a size of the fine pattern but, when the criterion is not met as a result of determination processing, moving to a next measurement area without measuring a size of the fine pattern.

Abstract: A pattern estimating method, wherein during exposure for forming the device pattern, a latent image of a monitor pattern which has the same pitch as an L/S pattern as the device pattern and has a narrower line width than the L/S pattern is formed in a mark area, after developing the device pattern, probing light is applied from a monitor head to the monitor pattern, and under the conditions for preventing generation of diffracted light of first-order or more, the intensity of zero-order light reflected from the monitor pattern is detected, so that the size of the device pattern is estimated on the basis of the prestored relationship between the device pattern size and the zero-order diffracted light intensity.

Abstract: An automatic focus control system comprises an electron beam lens column 1, a device control apparatus 2, and a host computer 3. In the host computer 3, an image processing section 32 and so on are provided. In case of measuring the critical dimension of the patterns in the wafer, after performing the global alignment adjustment, the power spectrum is calculated based on the SEM image of each measuring point in the wafer. After that, in case that the high-frequency component is included more than a prescribed standard value, without performing the automatic focus adjustment, the process for the pattern recognition is performed, and in case that the high-frequency component is included less than the standard value, the process for pattern recognition is performed just before the automatic focus adjustment. Therefore, it is possible to decrease the frequency (times) which performs the process for automatic focus adjustment; as a result, the throughput for measuring is improved.

Abstract: Analog image data a SEM are converted into digital data, and are processed by a spatial filtering processing, histogram processing, threshold value setting, three-valued image data processing, noise reduction and the like. Area of a pattern in the three-valued image data is calculated by a labelling and calculation processing, and a pattern is sequentially detected by comparing the area of the pattern with a reference area value. The comparison and detection of the same or similar patterns repeated in the SEM image are performed by using the area of the pattern, and are not performed by a shape of the pattern, thereby resulting a precise detection at high speed by using a microprocessor. Since it is possible to perform a pattern recognition from the area value even though the pattern does not have a characteristic, it is possible to precisely detect and recognize a pattern image in high speed.

Abstract: Analog image data a SEM are converted into digital data, and are processed by a spatial filtering processing, histogram processing, threshold value setting, three-valued image data processing, noise reduction and the like. Area of a pattern in the three-valued image data is calculated by a labelling and calculation processing, and a pattern is sequentially detected by comparing the area of the pattern with a reference area value. The comparison and detection of the same or similar patterns repeated in the SEM image are performed by using the area of the pattern, and are not performed by a shape of the pattern, thereby resulting a precise detection at high speed by using a microprocessor. Since it is possible to perform a pattern recognition from the area value even though the pattern does not have a characteristic, it is possible to precisely detect and recognize a pattern image in high speed.

Abstract: To prevent electric charge up from being accumulated on the plane scanned by an electron beam and further to improve the S/N ratio, an electron beam irradiating apparatus comprising: position information signal outputting section for outputting position information signals, in sequence to designate positions at which an electron beam is irradiated on a plane scanned by the electron beam, so as to designate the irradiation positions at random; and irradiation controller for-controlling the electron beam to irradiate the electron beam at the irradiation positions in response to the outputted position information signals. Further, to integrate an photoelectric signal over a sufficient time interval within the period of the pixel clock signal, the electric signal detecting circuit comprises a plurality of sample hold circuits and a selecting circuit for selecting and activating the sample hold circuits in sequence.

Abstract: An electron microscope comprises: a electron optical column 5 for allowing an electron beam aligned and focused by a lens 2, 3, 4 to pass therethrough; a specimen chamber 8 for receiving therein a sample 7 which is irradiated with the electron beam passing through the electron optical column; and a separating thin film 6, mounted so as to close an opening of the electron optical column on the side of the specimen chamber, for separating the electron optical column from the specimen chamber in a vacuum level.

Abstract: A critical dimension measuring equipment includes a filtering circuit for inputting image data from a SEM and performs spatial filtering processing of the image data, a histogram processing circuit implements histogram processing of the image data, a threshold value detection circuit obtains a threshold value based on a discriminant criteria method, a three-value conversion processing circuits implements three-value conversion of the image data based on the threshold value, a first calculation circuit obtains the area and perimeter of the bottom section of the pattern based on this data, a second calculation circuit obtains the diameters of the patterns based on this data, and a critical shape recognition circuit decide whether the pattern is circular or elliptical based on the critical diameter, calculates the diameter of the circle based on the area if the pattern is circular, and calculating the major axis and the minor axis of the ellipse based on the area and the perimeter if the pattern is elliptical.

Abstract: The fluorescent X-ray generated by elements when an X-ray is total reflected from a substrate surface is detected by a fluorescent X-ray detecting circuit; the fluorescent X-ray peak generated by the substrate element and the fluorescent X-ray peaks generated by contaminative elements are separated by a peak separating circuit; an integral intensity I.sub.0 of the fluorescent X-ray peak generated by the substrate element and integral intensities I of the fluorescent X-ray peaks generated by the contaminative elements are calculated by an integral intensity calculating circuit, respectively; and contaminative element concentrations N=N.sub.0 .multidot.(.eta..sub.0 / I.sub.0).multidot.(I / .eta.) (where N.sub.0 denotes the surface concentration of the substrate; .eta..sub.0 denotes the fluorescent yield of the substrate; and .eta.

Abstract: A contaminating-element analyzing method enables precise identification of contaminating elements and precise calculation of concentrations thereof by eliminating a broad peak waveform due to Rayleigh scattering and Compton scattering and a background waveform from a measured waveform of a contaminated sample. A blank sample or samples are irradiated by an X-ray beam under a constant condition to obtain a plurality of measured waveforms of fluorescent X-rays, and the plurality of measured waveforms are averaged to obtain a blank waveform. Then a contaminated sample is irradiated by the X-ray beam under the same condition as that for the blank sample to obtain a measured waveform of fluorescent X-rays. The blank waveform is subtracted from the measured waveform of contaminated sample, and then the contaminating elements are identified and the concentrations thereof are calculated on the basis of the waveform data after the subtraction process.

Abstract: In the method and apparatus for analyzing contaminative element concentrations, a fluorescent X-ray generated by elements when an X-ray is total reflected from the surface of a substrate is detected by a fluorescent X-ray detector; a peak of the fluorescent X-ray generated by a substrate element and peaks of the fluorescent X-ray generated by other contaminative elements are separated from the detected fluorescent X-ray waveform by a peak separating circuit; and the concentrations of the detected contaminative elements are calculated on the basis of the separated peaks by a calculating circuit. In the peak detection, in particular, the peaks of the contaminative elements to be analyzed are detected from the waveform. When other peaks are present within a predetermed number of channels (energy eV) before and after each detected peak, the channel numbers and the signal intensities between the respective peaks are extracted.

Abstract: A method of extracting a feature of an image, includes: a first step of performing a logarithmic conversion process for each pixel of an image taken by an electron microscope to carry out non-linear image enhancement; a second step of performing an N(N is a predetermined value) valued process for each pixel of the image underwent the logarithmic conversion process, threshold values for the N valued process being obtained by dividing the whole range of gray levels of the pixels by N, and gray level of the pixel being one of N constant gray level values by the N valued process; a third step of performing a partial differentiatial process in X- and Y-directions for each pixel of the image obtained by the second step, to make "0" the gray levels of pixels within the same area divided by the N valued process and make only the boundary between different areas divided by the N valued process to have a certain gray level; and a fourth step of detecting the boundary and extracting a feature of said image.

Abstract: Element identification and concentration calculation can be conducted with precision by correcting waveform distortion caused by the energy resolution of a detection system. A smoothing process is effected on a measured waveform of fluorescent X-rays obtained from an object to be measured. A device function of the detection system is obtained for each analytic element, based on the energy resolution of the detection system for a fluorescent X-ray energy value of each analytic element. A deconvolution process is effected on the measured waveform thus smoothed, by using the device functions of the detection system. Analytic elements are identified and concentrations of the analytic elements are obtained from the waveform data after the deconvolution process. The measured waveform is compensated for absorption in a beryllium window prior to smoothing.

Abstract: A contaminating-element analyzing method and an apparatus of the same are disclosed. Differential smoothing process is performed for a measured waveform of a fluorescent X-ray obtained from an object to be measured so as to detect a peak of the measured waveform, the object containing a contaminating element. A model function with variables which are initial parameters with respect to each peak of the measured waveform is provided so as to constitute a model waveform. A nonlinear optimizing process is performed using the method of least squares of the model waveform and the measured waveform so as to decide initial parameters of each model function and to obtain discriminated waveforms. A contaminating element is identified corresponding to each of the discriminated waveforms and obtaining an integrated intensity of a discrete waveform of each of the identified contaminating elements.

Abstract: In a gun (or lens) alignment control apparatus for an scanning electron microscope, a condenser (or objective) lens is controllably set to first and second conditions, respectively; first and second filament (or secondary electron) images obtained under the first and second conditions are inputted, respectively; the first and second filament (or secondary electron) images are processed to obtain first and second binarized images, respectively; the first and second binarized images are further processed to obtain first and second histograms, respectively; first and second coordinates at which the first and second histograms become maximum in frequency are detected, respectively; and exciting current for a gun (or lens) alignment coil is controlled so that the two coordinates match each other.

Abstract: To prevent electric charge up from being accumulated on the plane scanned by an electron beam and further to improve the S/N ratio, an electron beam irradiating apparatus comprising: position information signal outputting section for outputting position information signals, in sequence to designate positions at which an electron beam is irradiated on a plane scanned by the electron beam, so as to designate the irradiation positions at random; and irradiation controller for controlling the electron beam to irradiate the electron beam at the irradiation positions in response to the outputted position information signals. Further, to integrate an photoelectric signal over a sufficient time interval within the period of the pixel clock signal, the electric signal detecting circuit comprises a plurality of sample hold circuits and a selecting circuit for selecting and activating the sample hold circuits in sequence.

Abstract: An automatic focusing method for scanning electron microscopy. A scanning electron microscope is set in a low magnification mode to detect a taper portion of an object to be observed. The beam scanning whose direction is perpendicular to the taper portion is effected whenever objective lens control condition is changed at a first pitch, and the secondary electron signals obtained under these conditions are converted into video signals. The video signals are differential smoothed to calculate a sum of video signal absolute values. On the basis of the sum of the absolute values, an optimum objective lens control condition in the low magnification mode can be obtained. Sequentially, the microscope is set to a high magnification mode, and the objective lens control condition is further changed at a second pitch within a predetermined range with the optimum control condition in the low magnification mode as the center of the range.

Abstract: In a method of image restoration of an image picture obtained from a scanning electron microscopy, an image enhancement process and a differential process, such as a Sobel filtering process, are carried out separately at the same time onto image data having undergone ordinary smoothing process. Then, these two image data obtained from said two processes are synthesized together. The finally obtained image data, therefore, contain both characteristics which have been included in said two processes. So, fine changes existing in an original image can be reconstructed clearly in the finally obtained image picture.

Abstract: A pattern profile measuring method and apparatus for measuring the profile of a measuring portion of a pattern of a specimen placed on a specimen stage by controlling a deflector of a scanning electron microscope capable of setting a desired inclination angle of one of the specimen stage and an electron optical column, applying an electron beam to the measuring portion of the specimen, and image processing a secondary electron signal from the measuring portion.