Kabushiki Kaisha Toshiba

Yasuhiro Kaga

Fumio Komatsu

Isahiro Hasegawa

Kei Hattori

Hiroyuki Morinaga

Atsushi Onishi

Takema Ito

Masayoshi Yamasaki

A defect inspecting apparatus comprising:

Defect inspecting apparatus for semiconductor wafer

Even if an observing charged beam is irradiated upon an observation cross section obliquely from above, it is possible to obtain an observation image equivalent to that obtained when the observing charged beam is irradiated thereupon vertically from above. A wafer to be observed is mounted on the stage. The stage is moved by the stage control section on the basis of coordinate data given by the coordinate inputting section to such a position that an observed position of the wafer can be located just under the ion beam irradiating unit. The ion beam of the ion beam irradiating unit is irradiated upon the wafer surface vertically to form an observation cross section. On the other hand, an electron beam is irradiated from the electron beam irradiating unit upon the observation cross section obliquely from above at an inclination angle with respect to the ion beam irradiating unit. The secondary electrons emitted from the wafer surface are detected by the detector to generate video signals. These video signals are corrected on the basis of the inclination angle, and then converted into image signals equivalent to those obtained when the observation cross section is observed in the vertical direction from above.

Substrate cross-section observing apparatus

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. The beam scanning whose direction is perpendicular to the taper portion is effected. In the same way as in the low magnification mode, the secondary electrons signal obtained under these conditions are converted into video signals to obtain the optimum objective lens control condition in the high magnification mode. The optimum control condition obtained in the high magnification mode is determined as the control condition to determine the focal distance of the objective lens.

Automatic focusing method for scanning electron microscopy

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. The method comprises: a first step of calculating the distance at the bottom portion of the measuring portion of the pattern by image processing the secondary electron signal when the electron beam is applied to the measuring portion at an inclination angle of zero; a second step of obtaining the number of pixels at a taper portion of the measuring portion of the pattern by image processing the secondary electron signal when the electron beam is applied to the measuring portion at a first predetermined inclination angle; a third step of obtaining the number of pixels at the taper portion by image processing the secondary electron signal when the electron beam is applied to the measuring portion at a second predetermined inclination angle different from the first inclination angle; a fourth step of calculating the taper angle and depth of the pattern in accordance with the numbers of pixels of the taper portion obtained at the second and third steps and the first and second predetermined inclination angles; and a fifth step of obtaining the profile of the taper portion in accordance with the strength change of the secondary electron signal from the taper portion.

Method of and apparatus for measuring pattern profile

A pattern dimension measuring method for measuring the dimension of a measuring portion of a pattern of a specimen placed on a specimen stage by controlling a deflector of a scan type electron microscope capable of setting a desired inclination angle of the specimen stage a lens barrel, applying an electron beam to the measuring portion of the specimen, and image processing a secondary electron signal from the measuring portion, the method comprising: a first step of calculating the distance between top edges of the measuring portion of the pattern by image processing the secondary electron signal when the electron beam is applied to the measuring portion at an inclination angle of zero; a second step of obtaining the number of pixels at a taper portion of the measuring portion of the pattern by image processing the secondary electron signal when the electron beam is applied to the measuring portion at a first predetermined inclination angle which allows to observe the bottom edges; a third step of obtaining the number of pixels at the taper portion by image processing the secondary electron signal when the electron beam is applied to the measuring portion at a second predetermined inclination angle different from the first inclination angle which allows to observe the bottom edges; a fourth step of calculating the taper angle and height of the pattern in accordance with the numbers of pixels of the taper portion obtained at the second and third steps and the first and second predetermined inclination angles; and a fifth step of calculating the distance between the bottom edges of the pattern and the difference ratio between the top edge and bottom edge distances in accordance with the results calculated at the fourth step.

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Yokohama, Japan

Yasuhiro Kaga