JPH06208840A - Scanning type shape observing device - Google Patents

Abstract

PURPOSE:To improve the edge recognizing factor and the edge recognizing accuracy in the case of automatically recognizing an edge position of an outer shape of a sample, which is installed to a shape observing device, on the basis of an image by forming an edge part of the outer shape of the sample into a bright image in relative to the outside of the sample. CONSTITUTION:A hole is provided at a part under an edge part of an outer shape of a sample 3 of a sample installing device 13 so that a quantity of secondary electron and reflected light from the outside of a part under the edge part of the outer shape of the sample 3 is less than that of the case where a sample installing device is extended under the edge part of the outer shape. Edge recognizing factor and edge recognizing accuracy are thereby improved by performing a simple improvement to the sample installing device. Consequently, a special noise treating method and a special edge recognizing method or the like are not required to reduce a device cost and a computing cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning microscopic shape observation apparatus such as an electron microscope and a laser microscope.

[0002]

2. Description of the Related Art When automatically recognizing the outer edge position of a sample mounted on a sample mounting device of a shape observing device from a secondary electron image obtained by the shape observing device, conventionally, the position of the outer edge of the sample is below It was mounted on the extending plate-shaped sample mounting device. The edge portion is obtained as a brighter image than the outside of the sample. Therefore, if a binarized image is obtained using a sufficiently high threshold value, an image in which only the edge portion has a ring shape can be obtained. By obtaining this ring-shaped point sequence by the tracing method and obtaining the edge position coordinates, the outer shape of the sample is automatically recognized.

[0003]

However, when the noise component of the image outside the sample is large and a part of it is close to the brightness of the edge part, it is judged that there are a plurality of edges during automatic recognition, and the edge part In some cases, accurate recognition may not be possible.

If the edge portion is not sufficiently bright, a smooth ring-shaped image cannot be obtained, and the recognition accuracy is degraded. Problems such as the above occur, and the purpose is to solve these.

[0005]

According to the present invention, by improving a sample mounting device, an edge portion of an acquired image is made sufficiently bright with respect to an external portion of the sample, and a smooth ring shape which does not largely depend on selection of a threshold value. The present invention provides a scanning shape observation apparatus with improved edge recognition rate and recognition accuracy by making it possible to stably acquire the binarized image of.

[0006]

In the inside of the sample including the edge, an electron beam or the like for irradiating to obtain an image hits in the vicinity of the focal point, so that many electrons or the like generated from the sample are to be detected. In particular, edges are frequently generated due to the edge effect. Further, since the detector is arranged so that the generated electrons and the like can be easily detected, the detection efficiency is good. As a result, the inside of the sample including the edge portion looks bright.

In the following four embodiments, the image outside the sample is made dark by making the outside of the sample to be observed the reverse of the above-described principle of forming a bright image, thereby recognizing the edge recognition rate and the recognition accuracy. It is a shape observation device that improves (1) In order to allow the irradiated electrons and the irradiated light to reach the lower surface of the apparatus, which is sufficiently distant from the sample surface, a hole was made in the portion outside the sample at the edge observation location.

(2) A deep groove is provided in a portion outside the sample at the edge observation location so as to be away from the sample surface. (3) The portion outside the sample at the edge observation location was made a slope. (4) A material that absorbs the irradiation electron beam and irradiation light was attached to the portion outside the sample at the edge observation location.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. FIG. 1 shows a block diagram of a scanning shape observation apparatus of the present invention.

The electron beam a generated from the electron gun 1 is deflector 2
It is deflected in the x direction by x and is deflected in the y direction by the deflector 2y. The amount of deflection is from the CPU 6 to the DA converter 4 in the x direction.
And to the DA converter 5 in the y direction. The outputs of the DA converters 4 and 5 are connected to the deflectors 2x and 2y.

When the CPU 6 performs a reading operation on the AD converter 7, the electron b generated from the sample 3 is detected by the detector 8 and the converted value of the electric signal c is converted into a digital amount and taken into the CPU 6. Be done. The CPU 6 writes the value read from the AD converter 7 in the image memory 9. The contents of the image memory 9 are displayed on the display 10.

The sample 3 is mounted on the sample mounting device 13 and the observation position is controlled via the stage driving device 12. The stage movement amount is given from the CPU 6 to the stage control device 11. The output of the stage control device 11 is connected to the stage drive device 12.

(Embodiment 1) FIG. 2 shows an improvement of the sample mounting device 213. There is a hole 21 in the portion outside the sample at the edge observation location, and when the electron beam a is irradiated at the time of image acquisition, it reaches the lower surface 22 of the apparatus sufficiently far away. Here, the electron beam a is sufficiently distant from the focal point, and the electron beam a is widely spread. Therefore, the number of electrons generated from the outside of the sample is small, and it is far from the detector 28, so that it is difficult to detect the electrons. This embodiment can be used when observing a part of the outer shape.

(Embodiment 2) FIG. 3 shows an improvement of the sample mounting device 313. The principle is the same as that of the first embodiment. This embodiment is less likely to have a difference in brightness than the first embodiment,
The problem of deterioration of the strength of the sample mounting device due to the groove 31 can be avoided.

(Embodiment 3) FIG. 4 shows an improvement of the sample mounting device 413. The portion outside the sample 43 at the edge observation location is the slope 41, and when the electron beam is irradiated at the time of image acquisition, the electrons generated from the outside of the sample are difficult to fly toward the detector 48 and are therefore detected. Hateful.

(Embodiment 4) FIG. 5 shows an improvement of the sample mounting device 513. A member 51, which generates a small number of electrons due to electron beam irradiation, is attached to a portion outside the sample at the edge observation location. When the electron beam is irradiated during image acquisition, electrons are generated from the outside of the sample. Hateful.

[0017]

By using any one of the second to fifth embodiments or a combination thereof, it is possible to improve the edge recognition rate and the recognition accuracy when automatically recognizing the outer shape of the sample. According to the present invention, a special noise processing method, an edge recognition method, etc. are not required in addition to the improvement of a simple sample mounting apparatus, and the apparatus cost and the calculation cost can be reduced.

[Brief description of drawings]

FIG. 1 shows a block diagram of a scanning shape observation apparatus to which the present invention is applied.

FIG. 2 shows a sectional view of the first embodiment.

FIG. 3 shows a sectional view of the second embodiment.

FIG. 4 shows a sectional view of the third embodiment.

FIG. 5 shows a sectional view of the fourth embodiment.

[Explanation of symbols]

 3, 23, 33, 43, 53 sample 8 28, 38, 48, 58 detector 13 213, 313, 413, 513 sample mounting device a electron beam b electron generated from sample

Claims (1)

[Claims] 1. A scanning type shape for recognizing a shape by scanning a sample mounted on a sample mounting device with an electron beam or light from the upper surface of the sample and detecting the amount of secondary electrons or reflected light from the sample. In the observing device, the amount of secondary electrons or reflected light from outside under the edge portion of the outer shape of the sample is smaller than that in the case where the surface of the sample mounting apparatus extends under the outer edge portion of the sample. Mold shape observation device.