JPH09190790A - Scanning electron microscope and sample observation method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable magnetic samples to be observed and high-resolution images of nonmagnetic samples to be obtained. SOLUTION: To observe a magnetic sample, an inside magnetic pole piece 6 is mounted on an inside yoke 5, and an outside magnetic pole piece 9 is mounted on an outside yoke 8. To observe a nonmagnetic sample, the magnetic pole pieces 6, 9 are removed from the yokes 5, 8, and other magnetic pole pieces for constituting an ion lens type objective lens are mounted on the yokes 5, 8.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a scanning electron microscope for scanning a sample two-dimensionally with an electron beam, detecting a signal obtained from the sample by the scanning to obtain a sample image, and a sample observation in the scanning electron microscope. Regarding the method.

[0002]

2. Description of the Related Art FIG. 1 shows an objective lens of a scanning electron microscope. FIG. 1A shows a type in which a magnetic field peak of the objective lens is formed between an inner magnetic pole piece 1 and an outer magnetic pole piece 2. FIG. 1B shows the objective lens of FIG.
Indicates a type of objective lens (semi-in-lens type objective lens) in which the magnetic field peak of the objective lens is formed near the lower end faces of the inner and outer magnetic pole pieces 3 and 4. The magnetic field is leaking on the sample. By the way, the image resolution of the scanning electron microscope becomes higher as the spherical aberration of the objective lens becomes smaller, and this spherical aberration becomes smaller as the distance between the magnetic field peak of the objective lens and the sample becomes smaller. Therefore, when the working distance (WD) is the same in the scanning electron microscope including the objective lens of FIG. 1A and the scanning electron microscope including the objective lens of FIG. The scanning electron microscope equipped with the semi-in-lens type objective lens of b) is higher than the scanning electron microscope equipped with the objective lens of FIG.

[0003]

However, when observing a magnetized sample with a scanning electron microscope equipped with a semi-in-lens type objective lens, the lens magnetic field leaking onto the sample is greatly disturbed by the magnetic sample, and The problem arises that an image of the sample cannot be obtained.

On the other hand, in the scanning electron microscope equipped with the objective lens shown in FIG. 1A, the lens magnetic field does not leak onto the sample, so that the electron beam is not affected by the sample and a high quality image is obtained even on the magnetic sample. be able to.

Therefore, the magnetic sample is observed with a scanning electron microscope equipped with the objective lens shown in FIG. 1A, and the non-magnetic sample is observed with a scanning electron microscope equipped with a semi-in-lens type objective lens capable of obtaining a high resolution image. However, it is necessary to prepare two scanning electron microscopes having different types of objective lenses. This is very expensive and there must be a place to install them.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a scanning electron microscope and a scanning electron microscope capable of observing a magnetic sample and obtaining a high-resolution image of a nonmagnetic sample. It is to provide a sample observation method.

[0007]

Means for Solving the Problems A scanning electron microscope according to the present invention that achieves this object includes a yoke around which an exciting coil is wound, and an inner pole piece attachment member for attaching an inner pole piece to the inner yoke of the yoke. And an outer pole piece attachment member for attaching the outer pole piece to the outer yoke of the yoke, the inner and outer pole pieces being adjusted by adjusting the inner and outer pole piece attachment members. It is configured to be taken out through the. Further, the sample observation method in the scanning electron microscope of the present invention comprises a yoke around which an exciting coil is wound, an inner pole piece attachment member for attaching an inner pole piece to the inner yoke of the yoke, and an outer yoke of the yoke. An objective lens including an outer magnetic pole piece mounting member for mounting the outer magnetic pole piece is provided, and the inner and outer magnetic pole piece mounting members are adjusted so that the inner and outer magnetic pole pieces can be taken out to the outside through the sample chamber. In addition to using a scanning electron microscope, a plurality of inner pole pieces and outer pole pieces having different shapes are prepared, and when observing a magnetic sample, the inner and outer pole pieces that do not leak the magnetic field of the objective lens onto the sample are used. Inner and outer magnetic poles attached to the inner yoke and the outer yoke, respectively, and leak the magnetic field of the objective lens onto the sample when observing a non-magnetic sample. It is characterized respectively attached to the inner yoke and the outer yoke a.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The feature of the present invention is that an objective lens in which an inner magnetic pole piece and an outer magnetic pole piece are detachably attached In the configuration. When observing the magnetic sample, the inner pole piece and the outer pole piece for constructing the objective lens of the type shown in FIG. 1A are attached to the yoke, respectively, and when observing the nonmagnetic sample, Inner pole pieces and outer pole pieces for constituting the semi-in-lens type objective lens shown in FIG. 1B are attached to the yoke, respectively. The exchange of the magnetic pole pieces is performed through the opened sample chamber.

FIG. 2 shows a cross section of the objective lens of the scanning electron microscope of the present invention when observing a magnetic sample, and FIG. 3 is a view of FIG. 2 seen from the direction of arrow K. In FIG.
The inner yoke 5 has an inner magnetic pole piece 6 having the same diameter as that of the inner yoke 5.
2 are attached by means of male screws 7a to 7f (only 7a and 7d are shown in FIG. 2), and the outer yoke 8 has six male screws 10a to 7f each having an outer magnetic pole piece 9 having the same diameter as the outer yoke 8. 10f (only 10a and 10d are shown in FIG. 2), and the outer magnetic pole piece 9 is installed between the inner magnetic pole piece 6 and the sample S. Reference numeral 11 is an exciting coil wound around the yoke, and H is a notch.

In a scanning electron microscope equipped with such an objective lens, the magnetic field peak of the objective lens is formed between the inner magnetic pole piece 6 and the outer magnetic pole piece 9, and the magnetic field does not leak onto the sample. A magnetic field is not generated between the magnetic field and the magnetic sample, and a good quality image of the magnetic sample can be obtained by electron beam scanning without astigmatism.

Next, the case of observing a non-magnetic sample with high resolution will be described.

FIG. 4 shows the appearance of the scanning electron microscope. The exchange of the magnetic sample with the non-magnetic sample is performed in the sample chamber 12
The sample door 13 is opened and the test is performed. At the same time as this sample exchange, the magnetic pole pieces of the objective lens shown in FIG. 2 attached to the lowermost stage of the lens barrel 14 and located in the sample chamber are exchanged. In this replacement work, first, the male screw 10a-
10f is removed to remove the outer magnetic pole piece 9 from the outer yoke 8, and then the male screws 7a to 7f are removed to remove the inner magnetic pole piece 6 from the inner yoke 5. Then, magnetic pole pieces for constructing a semi-in-lens type objective lens are attached to the inner yoke 5 and the outer yoke 8, and then the sample door 13 is closed.

FIG. 5 shows a cross section of the objective lens after the attachment, and FIG. 6 is a view of FIG. 5 viewed from the direction of arrow K. In FIGS. 5 and 6, the same reference numerals as those in FIGS. 2 and 3 represent the same constituent elements. In FIG. 5, an inner magnetic pole piece 15 having the same diameter as that of the inner yoke 5 is attached by six male screws 7a to 7f (only 7a and 7d are shown in FIG. 5). 8
An outer magnetic pole piece 16 having the same diameter as that of the outer magnetic pole piece 16 is attached to the inner magnetic pole piece 15 and the outer magnetic pole piece 16 by six male screws 10a to 10f (only 10a and 10d are shown in FIG. 5). The end faces are located almost on the same plane.

In a scanning electron microscope equipped with such a semi-in-lens type objective lens, the magnetic field peak of the objective lens is formed near the lower end face of the pole piece, and secondary electrons generated from the sample by the magnetic field leaking onto the sample. Is wound up on the optical axis and detected by the secondary electron detector, so that a high-resolution secondary electron image is obtained.

[0015]

In the present invention, when observing a magnetic sample, a magnetic pole piece that prevents the magnetic field of the objective lens from leaking over the sample is attached to the yoke, and when observing a non-magnetic sample, the magnetic sample is not Since a magnetic pole piece that leaks the magnetic field of the objective lens is attached to the yoke, a high-quality image of the magnetic sample and a high-resolution image of the non-magnetic sample can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an objective lens of a conventional scanning electron microscope.

FIG. 2 is a diagram showing an objective lens of the scanning electron microscope of the present invention.

FIG. 3 is a diagram showing an objective lens of the scanning electron microscope of the present invention.

FIG. 4 is a diagram showing an appearance of a scanning electron microscope.

FIG. 5 is a diagram showing an objective lens of the scanning electron microscope of the present invention.

FIG. 6 is a view showing an objective lens of the scanning electron microscope of the present invention.

[Explanation of symbols]

1, 3, 6, 15 ... Inner pole piece, 2, 4, 9, 16 ... Outer pole piece, 5 ... Inner yoke, 7a, 7d, 10a-10
f ... Male screw, 8 ... Outer yoke, 11 ... Excitation coil, 12
... sample chamber, 13 ... sample door, 14 ... lens barrel, O ... optical axis, H ...
Notch, S ... Sample

Claims (2)

[Claims] 1. A yoke around which an exciting coil is wound, an inner pole piece attachment member for attaching an inner pole piece to the inner yoke of the yoke, and an outer pole piece for attaching an outer pole piece to the outer yoke of the yoke. A scanning electron comprising an objective lens composed of a piece mounting member, and the inner and outer pole piece mounting members being adjusted so that the inner and outer pole pieces can be taken out to the outside through a sample chamber. microscope. 2. A yoke around which an exciting coil is wound, an inner pole piece attachment member for attaching an inner pole piece to the inner yoke of the yoke, and an outer pole piece for attaching an outer pole piece to the outer yoke of the yoke. With a scanning electron microscope provided with an objective lens consisting of a piece mounting member, and by adjusting the inner and outer pole piece mounting members, the inner and outer pole pieces can be taken out to the outside through a sample chamber, A plurality of inner pole pieces and outer pole pieces having different shapes are prepared, and when observing a magnetic sample, the inner and outer pole pieces that do not leak the magnetic field of the objective lens onto the sample are attached to the inner yoke and the outer yoke, respectively. ,
A method of observing a sample in a scanning electron microscope, characterized in that, when observing a non-magnetic sample, inner and outer magnetic pole pieces that leak the magnetic field of the objective lens are attached to the inner yoke and the outer yoke, respectively.