Hitachi-High-Technologies Corporation

Mayuka Oosaki

Chie Shishido

Hiroki Kawada

Tatsuya Maeda

Ryo Nakagaki

Mitsugu Sato

Maki Tanaka

A system for controlling a tool-to-tool disparity between a plurality of scanning electron microscopes includes a measuring unit for measuring a tool-to-tool disparity between plural scanning electron microscopes based on information extracted from secondary electron images which are captured by imaging a reference pattern, a tool state monitoring unit for monitoring tool states of each of the plural scanning electron microscopes, and an output unit for displaying on a screen a relationship between the tool-to-tool disparity between the plural scanning electron microscopes and tool states of each of the plural scanning electron microscopes monitored by the tool state monitoring unit. The tool state monitoring unit monitors the tool states of each of the plural scanning electron microscopes while imaging the reference pattern by using each of the plural scanning electron microscopes.

Tool-to-tool matching control method and its system for scanning electron microscope

The present invention provides a charged particle beam apparatus used to measure micro-dimensions (CD value) of a semiconductor apparatus or the like which captures images for measurement. For the present invention, a sample for calibration, on which a plurality of polyhedral structural objects with known angles on surfaces produced by the crystal anisotropic etching technology are arranged in a viewing field, is used. A beam landing angle at each position within a viewing field is calculated based on geometric deformation on an image of each polyhedral structural object. Beam control parameters for equalizing the beam landing angle at each position within the viewing field are pre-registered. The registered beam control parameters are applied according to the position of the pattern to be measured within the viewing field when performing dimensional measurement. Accordingly, the present invention provides methods for reducing the variation in the CD value caused by the variation in the electron beam landing angle with respect to the sample with an equal beam landing angle and methods for reducing the instrumental error caused by the difference in the electron beam landing angle between apparatuses.

Charged particle beam apparatus and methods for capturing images using the same

A method of evaluating a resolution of a scanning electron microscope includes picking up a first image of a concave and convex pattern formed on a surface of a sample utilizing a first scanning electron microscope, picking up a second image of the concave and convex pattern on the sample utilizing a second scanning electron microscope, respectively processing the first image and the second image in order to evaluate unevenness in resolution between the first scanning electron microscope and the second scanning electron microscope, and determining whether a height of the concave and convex pattern as measured from a bottom thereof is sufficient so that no affection by a secondary electron emitted from the bottom of the concave and convex pattern is exhibited.

Sample and method for evaluating resolution of scanning electron microscope, and electron scanning microscope

A system for controlling a tool-to-tool disparity between a plurality of scanning electron microscopes includes a measuring unit for measuring a tool-to-tool disparity between plural scanning electron microscopes based on information extracted from secondary electron images which are captured by imaging a reference pattern formed on a wafer, a tool state monitoring unit for monitoring tool states of each of the plural scanning electron microscopes, and an output unit for displaying on a screen a relationship between the tool-to-tool disparity between the plural scanning electron microscopes and tool states of each of the plural scanning electron microscopes monitored by the tool state monitoring unit. The tool state monitoring unit monitors the tool states of each of the plural scanning electron microscopes while imaging the reference pattern formed on the wafer by using each of the plural scanning electron microscopes.

In the case of monitoring a resolution of a scanning electron microscope, it is required to prepare a sample and to use a measuring algorithm so as to reduce the pattern dependency of an index value of resolution to be measured in order to measure a variation in the size of an electron beam with a high degree of accuracy. According to the present invention, there is used a sample having a sectional shape which is appropriate for monitoring the resolution, that is, the sample has a pattern with such a sectional shape that a side wall of the pattern is inclined so as to prevent an electron beam irradiated on the sample from impinging upon the side wall of the pattern. With this configuration, it is possible carry out such resolution monitor that does not depend upon a sectional shape of a pattern.

A system for controlling a tool-to-tool matching between a plurality of scanning electron microscopes for pattern dimension measurement includes a measuring unit for, at regular intervals, measuring a tool-to-tool disparity between canning electron microscopes based on secondary electron image data, and measuring indicators indicating states of the microscopes, a tool-to-tool-disparity causing factor analyzing unit for analyzing a relationship between the tool-to-tool disparity and the values of the indicators measured by the measuring unit to estimate a factor that has caused said tool-to-tool disparity, and an output unit for displaying and outputting the tool-to-tool disparity causing factor estimated by the tool-to-tool-disparity causing factor analyzing unit.

A method for measuring a dimension of a pattern formed on a sample using a secondary electron image obtained by picking up an image of the sample using a scanning electron microscope includes: obtaining a secondary electron image of a sample by picking up an image of the sample using a scanning electron microscope; creating, using the secondary electron image, an image profile of a pattern whose dimension is to be measured, within the obtained secondary electron image; retrieving a model profile that matches best with the created image profile from a plurality of model profiles prestored that are obtained from respective secondary electron images of a plurality of patterns, the cross sections of the plurality of patterns being of known shapes and dimensions and being different in shape; and obtaining a dimension of the pattern using information of the retrieved model profile.

Measuring method and its apparatus

As measurement accuracy required for the scanning electron microscope (SEM) for measuring a pattern width becomes stringent, a technique of reducing the difference in a measured dimension between the SEM's is desired. However, the conventional technique of evaluating the difference in a measured dimension between the SEM's cannot separate the difference in a measured dimension between the SEM's themselves and a dimensional change resulting from deformation of the pattern itself. Moreover, the technique of reducing the difference in a measured dimension between the SEM's needs an operator for reducing the difference in a measured dimension between the SEM's for each measurement pattern shape. In this invention, a pattern at the same position is measured for a plurality of times with each SEM, and a different between extrapolated values of measured values obtained by the respective SEM's is calculated, whereby separation between the difference in a measured dimension between the SEM's and a dimensional change resulting from deformation of the pattern itself is made possible. Moreover, matching electron beam image profiles between the SEM's using an operator that simulates a difference in beam diameter between the SEM's makes it possible to reduce the difference in a measured dimension between the SEM's, not depending on a dimensional measurement pattern shape.

Scanning electron microscope, method for measuring a dimension of a pattern using the same, and apparatus for correcting difference between scanning electron microscopes

The present invention relates to an electron microscope which reduces a difference in measured values that occur due to a difference in resolution that cannot be fully adjusted which exists among electron microscopes, or occurs as time elapses, and a method for measuring dimensions. An operator adapted to compensate for changes of an electron image to be generated due to a difference in probe diameter is obtained in advance from electron images of one reference sample created by electron microscopes having different resolution (probe diameter). Then a compensation-measurement electron image which is equivalent to an electron image created under the same probe diameter by applying the operator for compensation, and the compensation-measurement electron image is used for measuring the dimensions.

Electron microscope, measuring method using the same, electron microscope system, and method for controlling the system

The present invention relates to a CDSEM (scanning electron microscope) capable of evaluating and presenting the measurement repeatability as a tool with a high degree of accuracy without being influenced by fluctuations in micro-minute shape that tend to increase with the microminiaturization of semiconductor patterns, and to a method for evaluating accuracy of repeated measurement using the scanning electron microscope. There is provided a function whereby when measuring a plurality of times the same part to be measured, by making use of a micro-minute pattern shape such as the roughness included in the pattern, pattern matching with a roughness template image is performed to correct two-dimensional deviation in position of the part to be measured on an enlarged measurement image acquired, and then an enlarged measurement area image is extracted and acquired. This makes it possible to eliminate variation in measurements caused by the micro-minute pattern shape.

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Yokohama, Japan

Mayuka Oosaki