JPS62136743A - Diaphragm device for electronic microscope - Google Patents

Abstract

PURPOSE:To increase the angle of a sample holder until contacting against an iris device and to increase the inclination angle of a sample without sacrificing the function of an euthentric mechanism by sliding an diaphragm along the direction of an axis for forming the euthentric mechanism. CONSTITUTION:An inclination body 10, a sample holder 12, an idle body 20, a movable rod 17, etc. for forming an euthentric mechanism are arranged on X-axis crossing perpendicularly with the optical axis Z of an electronic microscope while diaphragm 24 is arranged in the direction of X-axis immediately below the sample holder 12. Said diaphragm 24 is secured to an diaphragm stage 22 surrounding a lower magnetic pole chip 6 while a drive arm 25 is arranged continuously to said stage 22 in the perpendicular direction against X-axis. By sliding said drive arm 25 in the direction of X-axis, the diaphragm 24 is slided in the direction of X-axis. Consequently, the angle, with which the sample holder 12 is brought in contact with the iris device 21 can be increased without sacrificing the euthentric function and the inclination angle of sample can be increased.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a so-called side entry type sample tilting method in which a sample is inserted from a direction perpendicular to the optical axis in an electron microscope, an X-ray microanalyzer, an Auger microprobe, etc. The present invention relates to an apparatus, and particularly to an aperture device disposed directly below a sample.

[Conventional technology]

In general, a sample tilting mechanism is installed in the sample plane moving mechanism of an electron microscope, etc., and when the sample is tilted, there may be a deviation in height or a lateral change on the sample surface, i.e., the position relative to the optical axis. changes occur. The former appears as a change in focus, magnification, and camera length, and the latter appears as a shift in the field of view, which poses a major operational obstacle. For this reason, a so-called knee-centring goniometer has conventionally been used as a sample tilting device that does not shift the field of view even when the sample is tilted, and does not shift the focus even when the sample is moved.

As shown in FIGS. 3 and 4, an electron microscope employing this eucentric goniometer has an objective consisting of a yoke 1, an excitation coil 2, an upper magnetic pole piece 5, and a lower magnetic pole piece 6 inside the electron microscope body. A lens is arranged and the upper magnetic pole piece 5
, and the lower magnetic pole piece 6 is maintained with high precision by the spacer 7C). On the other hand, a stage 3 is installed above the yoke l, and a cylindrical inclined body 10 is rotatably attached to this stage 3 via a hair ring 9, and the rotation axis of the inclined body 10 is The Y axis is orthogonal to the electron beam optical axis Z. Further, a sample holder 12 is slidably inserted inside the inclined body 10 via a spherical bearing 11, and is rotatable in the Z direction and the Y direction by a Z pongee adjustment screw 13 and a YIli[il adjustment screw 15. is mated to. A sample S is placed f2 on the sample holding portion of the sample holder 12, and the sample S is disposed within the gap between the upper magnetic pole piece 5 and the lower magnetic pole piece 6 and as desired along the optical axis Z. Furthermore, a holder 16 is attached to the side wall of the yoke 1 facing the inclined body 10, and a moving rod 1 is mounted inside the holder 16.
7 is slidably fitted, one end of the movable rod 17 is in contact with an X-pongee adjustment screw 19, and the other end is in contact with a super moving body 20. The floating body 20 is supported by a spring (not shown) so that one end thereof can rotate three-dimensionally around a recess provided in the moving rod 17, and
A recess is provided at the other end of the floating body 20, and one end of the sample holder 12 is brought into contact with the recess. Reference numeral 21 denotes a diaphragm device disposed directly below the sample from the side wall of the yoke 1 so as to intersect with the sample holder 12.

To explain the sample movement with the above configuration, first, the sample movement in the X-axis direction is XIl! By rotating the II+adjustment screw 19, the moving rod 17 moves, and the sample holder 12
is pressed by the floating body 20 and moves in the X-axis direction. At this time, since the interior of the yoke 1 is vacuum, atmospheric pressure acts on the sample holder 12, and the tip of the sample holder 12 is always held close to the floating body 20.
Move while being pressed by.

Next, we will explain sample movement in the Y-axis or Z-axis direction.
When the Z pongee adjustment screw 13 or the YIilh adjustment screw 15 is rotated, the sample holder 12 rotates as the spherical bearing 11 rotates, but the tip of the sample holder 12 is always pressed against the floating body 20 due to atmospheric pressure. In addition, since the floating body 20 is rotatably supported three-dimensionally through the recess provided in the moving rod 17, the sample holder 12 slides inside the spherical bearing 11. The tip of the sample holder 12 rotates, and the trajectory drawn by the tip of the sample holder 12 is an arc centered on the recess provided in the moving rod 17.
Move in the axial direction.

Next, to explain the tilting operation of the sample, when the tilting body 10 is rotated, the sample holder 1 is rotated as the spherical bearing 11 rotates.
2 rotates to tilt the sample S, and performs a movement that satisfies the eucentric condition that the position of the sample viewed on the fluorescent plate does not move when tilted. That is, as shown in FIG. 7, when rotating the tilting body IO after moving the sample in the Y-axis and Z-axis directions, the tilting body I
Although the rotation axis of O and the axis of sample holder 12 are different,
Due to atmospheric pressure, the tip of the sample holder 12 is always held by the floating body 20.
The sample holder 12 rotates around the rotation axis (X) of the tilting body 10 because the floating body 20 is three-dimensionally rotatable. At this time, the plane created by the rotation of the floating body 20 is perpendicular to the goniometer axis (Y-axis), and therefore, when the sample moves, a certain point of the beam is always at the center of rotation for tilting, and the point on the fluorescent plate is always at the center of rotation for tilting. The position of the sample being viewed will not move.

[Problem that the invention seeks to solve]

In the above-mentioned conventional side entry type electron W4 microscope, the major challenges are to improve the resolution and to be able to tilt the sample significantly.

However, these two issues have mutually contradictory elements. That is, in order to improve the resolution, it is necessary to narrow the gap between the upper magnetic pole piece 5 and the lower magnetic pole piece 6 constituting the objective lens, but when the gap is narrowed, the inclination angle of the sample becomes smaller.

In addition, the aperture device 2 is a factor that reduces the inclination angle of the sample.
The existence of 1 is mentioned. Since this diaphragm device η21 is inserted between the lower magnetic pole piece 5 and the lower magnetic pole piece 6 together with the sample,
This is an obstacle to increasing the angle of inclination. That is, in the conventional apparatus described above, in order to satisfy the knee-centric condition, the sample holder 12, the floating body 20, and the moving rod 17 are arranged on the same axis, and as a result, the diaphragm device 21 is When the sample holder 12 is tilted as shown in FIG. 6, it hits the aperture device 21 and a large inclination angle cannot be obtained. In this case, in order to increase the inclination angle, it is possible to widen the gap between the upper magnetic pole piece 5 and the lower magnetic pole piece 6, but this creates the mutually contradictory problem of becoming an obstacle to improving the resolution described above. .

The present invention solves the above problems by arranging the aperture device in the same direction as the axis forming the eucentric mechanism, thereby ensuring resolution and making it possible to increase the tilt angle of the sample. This is the purpose.

[Means for solving problems]

For this purpose, the aperture device of the present invention, such as an electron microscope, is provided with a tilting body, a spherical bearing, a sample holder, a floating body, and a moving rod forming a eucentric mechanism on the X-axis perpendicular to the optical axis, and the sample holder A diaphragm member is arranged in the X-axis direction directly below the diaphragm, and the diaphragm member is fixed to a ring-shaped diaphragm stage surrounding the lower magnetic pole piece, and a drive arm is connected to the diaphragm stage at right angles to the X-axis direction. , the aperture member is made slidable in the X-axis direction by sliding the drive arm in the X-axis direction.

[Effect]

In the aperture device of the present invention, the aperture member slides along the direction of the axis forming the eucentric mechanism without impairing the function of the eucentric mechanism.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing one embodiment of the aperture device according to the present invention, FIG. 2 is a cross-sectional view along the X-axis of FIG. 1, and FIG. 5 is a diagram for explaining the tilt angle when tilting the sample. .

In the figure, 1 is a yoke, 2 is an excitation coil, 3 is a stage, and 5
6 is a lower magnetic pole piece, 6 is a lower magnetic pole piece, 7 is a spacer, 9 is a bearing, IO is an inclined body, II is a spherical bearing, 12 is a sample holder, 13 is a Z-axis adjustment screw, 16 is a holder, 17 is a moving rod , 19 is an adjustment screw, 21 is an aperture device, 22 is an aperture stage, 24 is an aperture member, 25 is a drive arm, 26 is a through hole, 27 is an adjustment screw, 29 is a bearing, and 30 is a stopper.

In FIG. 1, the explanation of the same structure as the conventional sample tilting device will be omitted. The difference from the conventional device described above is that in the conventional device, in order to satisfy the eucentric condition, a tilting body 10, a spherical bearing 11, a sample holder 12,
The floating body 20 and the movable rod 17 are arranged on the same axis, and as a result, the aperture device 21 has to be inserted from the direction intersecting the internuclear axis. However, in the present invention,
The point is that it is possible to arrange the C-squeezing device in the same direction as the axis forming the eucentric mechanism. That is, a ring-shaped aperture stage 22 is disposed below the sample holding portion of the sample holder 12 so as to surround the lower magnetic pole piece 6, and the aperture stage 2
A diaphragm member 24 is fixed in the same direction as the axis (X-axis) forming the eucentric mechanism on 2. Further, the aperture stage 22 is connected with a drive arm 25 on the Y-axis direction side thereof, and a through hole 26 is formed at the tip of the drive arm 25. On the other hand, an adjustment screw 27 is inserted from the side wall of the yoke 1 along the X-axis direction, passes through the through hole 26 of the drive arm 25, and is screwed into a female screw formed on the stage 3. Furthermore, a bearing 29 is interposed between the drive arm 25 and the through hole 26 so that the adjustment screw 27 can freely rotate relative to the aperture stage 22, and the drive arm 25 is placed on the axis of the adjustment screw 27. A stopper 30.30 is provided between the adjustment screw 27 and the aperture stage 2.
2 are configured to integrally interlock with each other in the X-axis direction.

To explain the operation, when the adjustment screw 27 is rotated, the adjustment screw 27 moves in and out of the female thread of the stage 3 and slides in the X-axis direction, and therefore the aperture stage 22 and the aperture member 24 also move along the X-axis direction. Sliding. The aperture member 24 is provided with a plurality of aperture holes (not shown) having different diameters, and by sliding the aperture member 24 along the The position of the axis Z can be selectively set. When the sample holder 12 is tilted as shown in FIG. 5, the angle until the sample holder 12 hits the diaphragm device 21 becomes larger.If the gap between the upper and lower magnetic pole pieces is the same, the angle of inclination is increased. It is possible to take

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made. For example, in the above embodiment, the adjustment screw 27 is inserted from the side wall of the yoke 1 along the X-axis direction, but the adjustment screw 27 may also be inserted along the Y-axis direction. It is sufficient that the aperture member 24 is inserted and disposed in the same direction as the shaft to be formed, and that the throttle member 24 is slidable so as not to interfere with the rotation of the floating body 20.

Further, the present invention is not limited to electron microscopes, but can also be applied to so-called side entry type sample tilting devices such as X-ray microanalyzers and Auger microprobes in which a sample is inserted from a direction perpendicular to the optical axis.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, since the aperture device is disposed in the same direction as the axis constituting the eucentric mechanism, when the sample holder 12 is tilted, the aperture device 21 The angle until it hits becomes larger, making it possible to take a larger angle of inclination.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the diaphragm according to the present invention, FIG. 2 is an X-axis sectional view of FIG. 1, FIG. 3 is a vertical sectional view showing a conventional diaphragm, and FIG. The X-axis sectional view of FIG. 3, FIGS. 5 and 6 are diagrams for explaining the tilt angle when the sample is tilted, and FIG. 7 is a diagram for explaining the eucentric condition. l... Yoke, 2... Excitation coil, 3... Stage, 5... Upper magnetic pole piece, 6... Lower magnetic pole piece, 7... Spacer, 9... Bearing, 10...・Slanted body, 11
... Spherical bearing, 12 ... Sample holder, 13 ... Z
Pongee adjustment screw, 15... Y pongee adjustment screw, 16... Holder, 17... Moving rod, 19... X pongee adjustment screw, 20
... floating body, 21 ... aperture device, 22 ... aperture stage, 24 ... aperture member, 25 ... drive arm,
26... Through hole, 27... Adjustment screw, 29... Bearing, 30... Strike, 7 bar. Applicant: JEOL Ltd. Representative Patent Attorney Hiroki Shirai (2 others) Aperture fL3
Fig. 5 Fig. 6

Claims (1)

[Claims] A tilting body, a spherical bearing, a sample holder, a floating body, and a moving rod forming a eucentric mechanism are arranged on the X-axis perpendicular to the optical axis, and a diaphragm member is arranged in the X-axis direction directly below the sample holder. On the other hand, the aperture member is fixed to a ring-shaped aperture stage surrounding the lower magnetic pole piece, a drive arm is connected to the aperture stage at right angles to the X-axis direction, and the drive arm is slid in the X-axis direction. A diaphragm device for an electron microscope or the like, characterized in that the diaphragm member is made slidable in the X-axis direction.