Hitachi, Ltd.

Japan Nuclear Fuel Co., Ltd.

Hiroshi Makihira

Shunji Maeda

Hitoshi Kubota

Yasuo Nakagawa

Minoru Yoshida

Takashi Hiroi

Kenji Oka

Toshimitsu Hamada

Yasuhiko Nakayama

Chie Shishido

Yukihiro Shibata

Asahiro Kuni

Satoru Fushimi

Makoto Udaka

Takanori Ninomiya

Yoshimasa Ohshima

Yoshitada Oshida

Yukio Kembo

Nobuyuki Akiyama

Yasuhiko Hara

Kazushi Yoshimura

Mitsunobu Isobe

Satoru Ezaki

Souhei Ikeda

Osamu Harada

Fumiaki Endo

A method and apparatus for sensing by a linear image sensor a two-dimensional image of an object to be sensed includes detecting a position of the object by a position sensor having a first resolution, picking up an image of the object being projected in a direction (V-scan direction) generally perpendicular to an internal scan (H-scan) direction of the linear image sensor in synchronism with relative movement between the object and the linear image sensor, periodically switching a pixel size along the V-scan direction between a plurality of predefined pixel sizes during the relative movement between the object and the linear image sensor in accordance with information of the relative movement detected by the position sensor, and producing from an output of the linear image sensor a two-dimensional image of the projected image having a second resolution of the object to be sensed. The second resolution is a higher resolution than the first resolution.

Method and apparatus for picking up 2D image of an object to be sensed

A pattern inspection method and apparatus in which an image of a first pattern formed on a sample and an image of a second pattern formed on the sample is detected. At least one of the first pattern image and the second pattern image is converted to a gray level so as to be substantially the same with each other by linear combination including a gain and offset. A defect of the sample is detected by using the first pattern image and the second pattern image at least one of which has been converted to the gray level and a result of the detection is outputted to an external storage or processor by a communication arrangement.

Defect inspection method and apparatus therefor

An image pickup device for sensing a two-dimensional (2D) image while causing a projected image of an object to be sensed being projected onto a linear image sensor to relatively move with respect to the linear image sensor in a direction (V scanning) perpendicular to the internal scan (H scan) direction of the linear image sensor. This device includes a position detector circuit that detects the position of the object to be sensed, and a pixel size modifier circuit for changing or modifying the setup configuration of a pixel size in the V scan direction of the linear image sensor on the basis of a position detection signal indicative of the position of the to-be-sensed object as detected by the position detector circuit. The pixel size modifier circuit is operable based on the object position detection signal to periodically change the interval of H-scanning start pulses of the linear image sensor.

A pattern checking method wherein an image of a certain position of one pattern is detected; the detected image is positioned with respect to an image of a position corresponding to the certain position, in a reference pattern image; and the positioned images are compared with each other, whereby a discrepant place among these positioned images is judged as a defect the positioning operations of the images of the detected patterns are controlled based upon either pattern information such as density of the images of the detected patterns, or information obtained from the positioning operations for images of other positions in the patterns. An image sensor unit for detecting images of patterns is constructed which has such a structure that a plurality of one-dimensional image sensors functioning as a pattern detector are arranged in a two-dimensional form, and an output of a certain one-dimensional image sensor for imaging a certain position of one pattern is delayed for a predetermined time period, and also both of an output of an one-dimensional image sensor adjoining the first-mentioned one-dimensional image sensor, which images the same position of the same pattern, and the delayed output of the certain one-dimensional image sensor are sequentially added to derive a summation output. The image sensor unit is inclined at a predetermined angle with respect to a plane perpendicular to the reflection light from the patterns, and the reflection light from the patterns is focused via a confocal focusing optical system onto this image sensor unit.

Pattern checking method and checking apparatus

A defect inspection method and apparatus therefor for a pattern to be inspected having a plurality of chips formed so as to be identical detect an image signal of a pattern to be inspected and when the image signal is to be compared with a detected image signal of an adjacent or separated pattern to be inspected on the substrate, convert the gray level so that the brightness of each of two image signals for comparing one or both of the detected image signals is almost identical in the local region by linear conversion having a gain and offset, and when a pattern is inspected using it, highly sensitive defect inspection for a pattern to be inspected for detecting a defect of a semiconductor wafer can be realized.

The inventive pattern detection method and apparatus produce, from an optical image of a pattern in attention and an optical image of a pattern which should be identical to the pattern in attention, an optical image by merging the images, with a relative phase shift being imposed, and pattern information is detected or observed in the merged optical image or a signal produced from the optical image through the conversion with an opto-electric transducer means.

Method and apparatus for pattern detection

A method and apparatus for detecting a defect in a circuit pattern by detecting a gray image signal from each of a plurality of circuit patterns as objects of inspection, which circuit patterns have been fabricated so as to be identical with one another, and detecting a defect as a difference of edge position between two circuit patterns by comparing the detected gray image signal of one circuit pattern with the detected gray image signal of another circuit pattern.

Method and apparatus for detecting patterns

Method of and apparatus for checking the geometry of multi-layer patterns for IC structures having identical functions, each of the multi-layer patterns including layer patterns arranged in different level layers, wherein electrical image signals corresponding to any two of the multi-layer patterns and having more than two levels are registered with each other and then compared to determine unmatched and matched portions. The comparison of the registered electric image signals may be performed with respect to their amplitude or their gradients. The registration and comparison of two electric image signals may be repeated for all of the layer patterns with the matched portions being no longer subjected to the registration and comparison. A defect detection signal is produced from finally unmatched portions, if any, of the electric image signals having undergone the said registration and comparison.

Method of and apparatus for checking geometry of multi-layer patterns

A method of auto-focusing suitable for fine patterns of LSIs and an apparatus therefor, particularly applied for checking the geometry of a circuit pattern of a semiconductor device formed on an LSI wafer. A stripe pattern is projected on a specified location on an object to be checked and contrast of an image of the stripe pattern is used for focusing. The specified location is imaged by an optical system and detected simultaneously by two detectors. A position at which contrast of an output signal of one detector coincides with that of the other detector is determined to be an in-focus position. Am image of a multi-layer pattern representative of the circuit pattern is focused on another detector disposed at the in-focus position and detected for checking. The output signal of the detector is divided by mean brightness of the stripe pattern image so as to be normalized. Since the two detectors produce their output signals simultaneously, the difference between the output signals is normalized to improve accuracies of computation.

Automatic focusing method and apparatus utilizing contrasts of projected

A pattern defect is detected in accordance with the difference between a pair of patterns. The patterns are scanned and imaged to obtain first and second binary signals. A positioning error between the patterns is two-dimensionally detected during the scanning with respective first and second binary signals delayed by a prescribed amount so that each of the picture elements in a prescribed area of a two-dimensional image, delayed and cut out two-dimensionally, corresponding to one pattern, is compared with a specified picture element in a predetermined area of an image delayed and cut out two-dimensionally corresponding to another pattern. The result of the comparison is statistically summed to derive a positioning error by detecting the position shown as an extreme value from the summed values. The positioning error is corrected by two-dimensionally shifting at least one of the delayed binary signals. The corrected binary signals are then two-dimensionally compared with each other.

Method of detecting pattern defect and its apparatus

In a method and apparatus for detecting the edge of a fine pattern formed on a specimen such as a fine circuit pattern formed on a semiconductor element or the like, there is prepared a predetermined model waveform based on theoretical secondary electron emission from the edge portion. Secondary electrons emitted from successive scanning points across the pattern edge portion through the irradiation of a scanning electron beam thereonto are detected to produce an actual signal waveform reflecting the secondary electron emission from the pattern edge portion. The actual signal waveform is compared with the model waveform, and one of the scanning points at which the highest coincidence exists between both the actual and model waveforms, is determined as a position of the pattern edge.

Method and apparatus for detecting edge of fine pattern on specimen

Disclosed is a shape detecting apparatus comprising a slit projector for projecting a slit bright line on a number of objects arrayed in a line, an image forming lens for forming the bright line image, an image scanning mechanism for the bright line image formed through the image forming lens in a height direction of the object and a one-dimensional image sensing device for self-scanning the bright line image formed therein with an array of image sensing elements orthogonal to the scanning direction by the image scanning mechanism.

Shape detecting apparatus

An apparatus for inspecting the outer peripheral surface of a cylindrical object is disclosed, in which the light in slit form is radiated on the surface of an object such as a nuclear fuel pellet at an angle thereto, the light regularly reflected on the surface is detected by a detector, the detected image signal is quantized at threshold values higher and lower than an average level, and the binary signals are used to detect surface losses separately from an unground part and a metal inclusion as a first detection process. The diffused light is radiated onto the surface of the nuclear fuel pellet at an angle thereto, parallel light rays are radiated onto the surface from the direction perpendicular thereto, the light reflected from the surface of the object is detected by a detector from the direction perpendicular to the surface, the detected image signal is quantized at a threshold level lower than an average level of the image signal for the normal surface, and the binary signal is used to detect, as a second detection process, a crack and a pit separately from a chip, said crack, pit or chip included in surface missing defects detected in said first detection process. The surface defects of the nuclear fuel pellet or the like are thus detected by separating them into at least three types including a chip, an unground part and a metal inclusion, and a crack and a pit.

Method and apparatus for appearance inspection

A surface defect inspection system comprises an image pick-up device for picking up an image by sequentially scanning the surface of an object two-dimensionally, a threshold circuit for quantizing the image signal produced from the image pick-up device as a binary code, a pattern feature extracting device for making calculations for extracting the features of image patterns from the quantized signal in synchronism with the scanning, and for temporarily storing the result of the calculations, a pattern region end decision device for deciding that individual pattern regions have ended in one direction, and a defect decision device for reading out from the pattern feature extracting device the result of the calculations on the pattern features corresponding to the positions each of the patterns in the direction perpendicular to the one direction each time of the decision that each pattern region has ended, so that the feature of each pattern scanned is compared with a predetermined reference, thus deciding and an indication of producing the presence or absence of a defect.

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Yokohama, Japan

Hiroshi Makihira