Hitachi-high-technologies Corporation

Hitachi, Ltd.

Atsushi Kobaru

Hiroki Kawada

Katsuhiro Sasada

Hidetoshi Morokuma

Sho Takami

Kouichi Yamamoto

Norio Satou

Kunio Nakanishi

Hideyuki Kazumi

Tadashi Otaka

Akira Ikegami

Koichiro Takeuchi

Satoshi Ikeda

Seiko Oomori

Atsushi Takane

Mitsuji Ikeda

Tatsuya Maeda

The SEM has a dynamic range reference value setting unit for setting dynamic range reference values, a dynamic range adjustment unit for receiving an observation image signal delivered out of a secondary electron detector, adjusting the dynamic range of the observation image signal on the basis of the dynamic range reference values and outputting the thus adjusted observation image signal as an observation image signal after adjustment, a display image generation unit for determining luminous intensity levels of individual pixels of an image to be displayed based on the observation image signal after adjustment to generate a display image, a histogram generation unit for generating a histogram of luminous intensity levels of the display image and extracting, as a luminous intensity peak value, at which the frequency of luminous intensity is maximized, and a display unit for displaying the generated histogram and the extracted luminous intensity peak value.

Scanning electron microscope and image signal processing method

In a method and apparatus for removing artifacts from an image generated a charged partial beam scanning device, a scanning method is determined, and the frequency of an artifact appearing on an image can then be determined, based on scanning method. A step, a frequency domain for removing an artifact can be determined from the vertical and horizontal widths determined by experimentation in advance with respect to the frequency position Photography is performed to obtain an image, which is Fourier transformed and the determined frequency domain is replaced, for example, by '0.' The resulting image is subjected to inverse Fourier transformation, and displayed and stored. The flow of such processing enables decreasing an artifact appearing on an image, depending on a scanning method. The frequency domain (vertical and horizontal widths) that is to be eliminated and a method for replacement by '0' are determined in advance, depending on the kind of inspected samples and a method can be selected depending on the kind of samples.

Charged particle beam apparatus

In a scanning electron microscope, an optimum scanning method for reducing the amount of deflection of a primary electron beam and secondary electrons is determined to acquire stable images. An energy filter is used to discriminate between energy levels. The change in yield of obtained electrons is used to measure the variation in specimen potential. The time constant of charging created during electron beam irradiation is extracted. The scanning method is optimized based on the extracted time constant to reduce the distortion and magnification variation that appear in a SEM image.

Scanning electron microscope having time constant measurement capability

An image forming method and a charged particle beam apparatus suitable for suppressing the inclination of charging when scanning a two-dimensional area with a charged particle beam. A third scanning line located between a first scanning line and a second scanning line is scanned. After the first, second and third scanning lines have been scanned, a plurality of scanning lines are scanned between the first and third scanning lines and between the second and third scanning lines.

Image forming method and charged particle beam apparatus

An object of the present invention is to provide a synthesized signal forming method and an apparatus thereof for realizing both noise reduction and dosage reduction when synthesizing signals detected based on scans performed on a charged particle beam. In order to achieve the above object, with a method that synthesizes signals detected based on a plurality of scans performed on a charged particle beam to form a synthesized signal, a multiplication is performed among a plurality of signals obtained by the plurality of scans and, at the same time, for a multiplied signal, a calculation is performed in which an inverse of the number of previous scans is used as an exponent.

A charged particle beam apparatus for measuring and inspecting a sample having some parts in focus and other parts out of focus in an image due to the effect of the roughness of the sample surface is disclosed, in which in order to acquire a clear image of the whole or a predetermined area in the image, the focus adjustment conditions for each point in the area to be scanned by the charged particle beam are determined in advance, and the focus adjustment conditions thus determined are applied selectively to the patterns formed under the same fabrication conditions as the sample for which the focus adjustment conditions are determined.

A scanning method for a scanning electron microscope is provided which minimizes a degradation in dimension measuring accuracy caused by a shrink of a specimen. A time between the first and the second scan over the same location on the specimen is shortened by changing the scanning order of scan lines to enable the scanning to be performed successively while the shrink is small.

Method of measurement accuracy improvement by control of pattern shrinkage

An apparatus using charged particle beam is provided with means for detecting positional difference between a target position on a chip pattern within an observation visual field of a microscope after displacing a sample stage thereof and a predetermined position within the visual field, means for storing the detection result and means for determining a new displacement target position for displacement to the predetermined position in subsequent observation while taking into account of the positional difference stored previously and the displacement target position used at the time of storage. When observing another wafer on which the same patterns with the same alignment as the previous one are printed or another pattern on the same wafer, the previous sample stage displacement target designation position is also modified while taking into account of the previous observation visual field position deviation which is registered to the corresponding observation position, and the stage is displaced according to the designation position. Thereby, quick and correct displacement of the observation position within an observation visual field can be realized.

Apparatus using charged particle beam

An electron beam is focused on a specimen by a focusing lens. A light beam is incident on the position of irradiation of the specimen with the electron beam and the reflected light beam is detected by a linear light detector. The output of the detector is used to measure the height of the specimen at the position of irradiation of the electron beam. The specimen is moved in a plane perpendicular to an optical axis of the focusing lens. A specimen height measuring device carries out the height measurement of the specimen at a position to be observed on the specimen and at positions thereon which are in the vicinity of the position to be observed, when those positions are located at the position of irradiation of the electron beam. The specimen height measuring device averages the measured values so as to produce a focusing correction signal on the basis thereof and controls the focusing lens on the basis of the focusing correction signal.

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Hitachinaka, Japan

Atsushi Kobaru