JPS6352423B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for minutely moving a sample to be observed using an electron microscope or the like to a desired position.

As shown in FIGS. 1 to 3, the conventional sample moving device is installed in a sample chamber 2 below a lens barrel 1 of an electron microscope, etc., and moves a sample 4 on a sample stage 3 in X, Y, Z, etc. It is designed to be able to move in each direction of R and T.

Here, the X direction is an axis (optical axis;
Hereinafter, for convenience, this axis will be referred to as the O axis. ), and the Y direction refers to the direction perpendicular to the X direction in a plane that intersects the O axis at right angles.
The Z direction refers to the direction parallel to the O axis, and the R direction refers to the direction in which the sample 4 is rotated within the XY plane.
The T direction refers to the direction in which the sample 4 is rotated about an axis that is perpendicular to the O axis.

In conventional sample moving devices of this type, in many cases, the center of rotation in the T direction intersects with the O axis so that the working distance WD and irradiation position do not change even if the sample 4 is rotated in the T direction. It is set to pass through the electron beam irradiation position A.

However, such conventional sample moving devices have the following problems. In other words, in order to bring out the best performance in scanning electron microscopes, etc., it is necessary to make the working distance WD as small as possible. However, when observing a large sample 4, as shown in Fig. In such a case, the rotation angle θ in the T direction is significantly restricted.

Therefore, if you want to increase this angle θ,
The sample 4 is moved in the Y direction or Z direction and shifted in the direction of arrow B or C in FIG. 4. However, such operations are time-consuming and place a heavy burden on the operator.

Furthermore, when observing a sample that is thicker than the reference, the beam irradiation position A is above the rotation center in the T direction, so the risk of interference between the sample 4 and the objective lens 5 increases.

Furthermore, if an attempt is made to increase the T-direction rotation angle θ, mechanical components of the sample moving device may interfere with the lens barrel 1 and the objective lens 5.

In order to prevent such interference and damage to the sample 4 and other parts, the shapes of the lens barrel 1 and objective lens 5, the size and thickness of the sample 4, the T-direction rotation angle θ,
It is necessary to consider six factors: the Y-direction position and the Z-direction position.

However, considering all of these six factors places a heavy burden on the operator, and it is nearly impossible to avoid interference.

Furthermore, due to the demand for automation of sample moving devices, the movement of the sample is now performed by driving a motor or the like. In this case, the sample is moved at high speed and the operator's senses are not available, further increasing the risk of interference.

The present invention aims to solve these problems, and provides a sample moving device that allows the sample to be moved freely within a range that does not cause interference, while also completely preventing interference. The purpose is to

For this reason, the sample moving device of the present invention includes a sample stage on which a sample can be placed and two-dimensionally moved in a direction intersecting the optical axis in the vicinity of the objective lens provided at the lower end of the lens barrel; A sample stand rotation drive mechanism capable of rotating the sample stand about a rotation axis that is perpendicular to the optical axis; A first interference member having a similar shape (including the same shape) to the projected image of the sample and a second interference member having a similar shape (including the same shape) to the projected image of the sample onto the plane are formed, and Interference member movement of moving the second interference member in the same manner as the projection image of the sample onto the plane in conjunction with the movement of the sample in order to prevent contact between the lens barrel and the objective lens and the sample. A mechanism is provided, and the second interference member moves and contacts the first interference member,
The present invention is characterized in that a detection section is provided that detects the approach of the sample moving mechanism and the lens barrel and objective lens and stops the movement of the sample.

Hereinafter, a sample moving device as an embodiment of the present invention will be explained with reference to the drawings. FIG. 5 is a side view showing the wall portion of the sample chamber in cross section, FIG. Figure 7 is the − of Figure 6.
Figure 8 is a partial cross-sectional view along the arrow line.
Fig. 9 is an enlarged cross-sectional view in the direction of the - arrow in the figure; Fig. 9 is a cross-sectional view showing a modification thereof corresponding to Fig. 6;
Each figure is a side view showing a modified example of the fixed end bracket, and FIG. 12 is a side view showing another modified example corresponding to FIG.
The same reference numerals as in Figures 4 to 4 indicate almost the same parts.

As shown in FIGS. 5 to 7, this device is installed in a sample chamber 2 below a lens barrel 1 of a scanning electron microscope, etc., and a sample 4 on a sample stage 3 is
It is designed to be able to move in each of the Z, R, and T directions.

The mechanism for moving the sample in each direction will be explained below. First, a sample stage 3 on which a sample 4 can be placed is provided, and this sample stage 3 is rotatably moved in the R direction by an R direction drive device (not shown).
is supported by

Further, this moving table 6 is supported by a moving table 7 so as to be movable in the Y direction along a rail 7a by a Y direction driving device (not shown).
is supported by the frame 8 so as to be movable in the X direction along the rail 8a by an X direction drive device (not shown).

Further, one end of the frame 8 is rotatably supported by a Z-direction movable table 9 via a rotating shaft 8b, and is also rotatably supported by a T-direction drive device (not shown) around the rotating shaft 8b. It is designed so that it can be rotated.

The movable stage 9 is supported by the sample chamber 2 so as to be movable in the Z direction along a rail 9a by a Z direction drive device (not shown).

By the way, the rotation axis 8b of the frame 8 is the optical axis (O axis).
It is provided so as to be perpendicular to the electron beam irradiation position A and to pass through the electron beam irradiation position A. Therefore, the sample stage 3 can be rotated around the rotation axis 8b that is perpendicular to the O-axis and intersects with the O-axis at the electron beam irradiation position A using the frame 8 and the T-direction driving device (not shown). A sample stage rotation drive mechanism M is configured.

In this way, by moving each moving stage 6, 7 or rotating the sample stage 3, the sample 4 can be moved in the X, Y,
The sample 4 can be moved two-dimensionally along each direction R, and the sample 4 can be rotated in the T direction by rotating the frame 8 about its rotation axis 8b. Furthermore, by moving the moving stage 9, the sample 4 can be moved in the Z direction.

Furthermore, an interference prevention mechanism is provided within the sample chamber 2. That is, a fixed end bracket 10 is provided on a plane P perpendicular to the rotation axis 8b, and this fixed end bracket 10 is fixed to the sample chamber 2. This fixed end bracket 10 is provided with an electrical stopper 12 as a first interference member via a spring 11. The shape of this electric stopper 12, as seen from the - arrow direction in FIG.
It is constructed to have a slightly larger outline with a similar shape.

A plurality of contact type switches 13 constituting a detection section are interposed between the fixed end bracket 10 and the electric stopper 12, and these switches 13 are connected as shown in FIG. and is pulled out from the high mesh seal 14.

That is, when the electrical stopper 12 is pushed up and even one of the switches 13 makes contact, the wiring drawn out to the outside becomes electrically conductive.

When conduction occurs between the wires in this manner, a risk of interference is detected by the operation of a detection circuit (not shown).

Accordingly, if the movement of the sample 4 is manual, an alarm is issued and the operator stops the movement, and if it is automatic, a signal is sent to the drive mechanism to stop the movement of the sample 4.

Further, on the plane P, a sample projection member 4' is provided as a second interference member having the same contour as the same-sized projection image of the sample 4 on the plane P, and
A sample stage projection member 3', a mobile stage projection member 6', 7', and a rail projection member 7' having the same contour as the same-sized projection image of the sample stage 3, moving stages 6, 7, and rail 7a onto the plane P. A is provided.

The movable table projection member 7' is fixed to the rotating shaft support member 8c of the frame 8 with a screw 21a, and a rail projection member 7'a is mounted on the movable table projection member 7' along the Y direction. A movable stage projection member 6' with a sample stage projection member 3' is movable along the Y direction on this rail projection member 7'a.

The sample projection member 4' is attached to the sample stage projection member 3' with screws 21b so that the sample 4 can be replaced.

Further, the movable table projection member 6' is configured to be able to move in the Y direction along the rail 7'a in conjunction with the movement of the movable table 6 in the Y direction.

In FIG. 7, the movement of the moving table 6 in the Y direction is transmitted by a pinion 17 that meshes with a rack 16 provided on the lower surface of the moving table 6, and the rotational movement of the Y direction movement transmission shaft 15. . Incidentally, the Y-direction movement transmission shaft 15 is formed with a spline groove 15a as shown in FIGS.
By engaging the key pin 18 provided on the pinion 17 with the key pin 5a, the rotation of the Y-direction movement transmission shaft 15 is transmitted to the pinion 17.

Further, as shown in FIG. 6, rotation is transmitted from the Y-direction movement transmission shaft 15 to the pinion 20 by the key 20a, so that the Y-direction movement transmission shaft 15
When the pinion 20 rotates, the pinion 20 rotates, and the rack 19 that meshes with the pinion 20 and the movable table 6' fixed to the rack 19 move in the Y direction in the same way as the movable table 6.

Note that even if the moving tables 6 and 7 are moved in the X direction, the rack 16, pinion 17, and key pin 18 remain in the Y direction.
Since they move simultaneously on the directional movement transmission shaft 15, the movement of the movable tables 6 and 7 in the X direction is not hindered.

Further, the sample projection member 4' is replaced each time depending on the thickness and size of the sample 4.

Furthermore, these projection members 3', 4', 6',
7', 7'a are the original members 3, 4, 6,
7 and 7a, and the electric stopper 12 is arranged slightly below the horizontal positional relationship with the lens barrel 1 and objective lens 5.

With the above configuration, when the sample 4 is moved in the Y, T, and Z directions, the sample projection member 4' moves equal to the projection of the sample 4 in the T-axis direction. Lower pole lower surface 5a and side wall surface 5
When approaching b, the sample projection member 4' pushes up the electric stopper 12 before they interfere, and
By contacting the switch 13, the danger of the sample 4 coming into contact with the objective lens 5 is immediately detected, and the movement of the sample 4 is stopped.

In this case, the shapes of the lens barrel 1 and the objective lens 5, the size and thickness of the sample 4, the rotation angle θ in the T direction, and the Y
All six factors are considered: directional position and Z-direction position. Therefore, interference can be completely prevented, and damage to the sample 4 and the sample moving mechanism can also be prevented.

Furthermore, since the stoppage of movement of the sample 4 can be obtained as an electrical signal, it is suitable for automation of the apparatus.

Furthermore, since interference can be completely prevented, it is possible to safely pursue the sample position that brings out the best performance of the electron microscope, etc. Furthermore, the burden on the operator is drastically reduced, and the operating time can be significantly shortened.

Note that even when there is no movement of the sample 4 in either or both of the Z direction and the R direction, interference between the lens barrel 1 and the objective lens 5 and the sample 4 can be prevented in the same way.

In addition, in a sample moving mechanism in which the sample 4 does not move in the Y direction, a support member 7'' corresponding to the moving stage 7 is fixed to the rotating shaft support member 8c, as shown in FIG. ' is fixed by a screw 21b.

When there is no movement in the Y direction, such a simple interference prevention mechanism can effectively prevent interference.

By the way, when using the electric stopper 12,
It is also conceivable that the movement of the sample 4 may not be stopped in time due to a delay in the electrical reaction.

Therefore, as shown in FIG. 10, instead of using the electrical stopper 12, the lower and side surfaces of the fixed end bracket 10 may be made into the same shape as the electrical stopper 12 to form a mechanical stopper 10'. When such a mechanical stopper 10' is used, the interference member provided on the rotating shaft support member 8c comes into contact with the mechanical stopper 10', so that the movement of the sample 4 is forcibly and instantaneously stopped. . Therefore, interference can be more reliably prevented.

Further, as shown in FIG. 11, an electric stopper 12 may be attached to the fixed end bracket 10, and may be used in combination with a safety stopper 22 as a mechanical stopper having a similar shape. Due to this mechanism, sample 4
Safe and reliable operation is possible whether the movement is automatic or manual.

Furthermore, as shown in FIG. 12, the rotating shaft 8b is extended and taken out of the sample chamber 2, and the rotating shaft 8b
Attach the support plate 23 to the end of the plane P (fifth,
(See Figure 7) Interfering member group 25 with the same shape as the upward projected image
The interference member group 25 is supported by the support plate 23 so that the interference member group 25 is located on a plane P' parallel to this plane P, and the interference member group 25 and the interference member group 25 are fixed to the outside of the sample chamber 2 and are connected to each other via a spring 11 at the lower end. Fixed end bracket 10 with electrical stopper 12 (this fixed end bracket 1
A switch 13 is connected between 0 and the electrical stopper 12.
is interposed. ) may constitute an interference prevention mechanism.

Here, the interference member group 25 refers to most of the members on the plane P, namely members 3', 4', 6', 7',
7'a, 8, 15, 19, 20, 20a, 21a,
21b. In other words, in this interference member group 25, the sample 4 etc. is Y,
It is linked with the sample moving mechanism so that it moves simultaneously with these objects when moved in the T and Z directions.

At this time, a vacuum holding plate 24 is required to maintain the vacuum inside the sample chamber 2.

In this way, by providing the interference member group 25 and the electric stopper 12 outside the sample chamber 2,
The operator can directly grasp the possibility of interference between members, which facilitates replacement and operation of the sample projection member 4'.

In addition, the electrical stopper 12 and each projection member 3' to
7' and 7'a may have the same outline as the same magnification projection image of the corresponding member, or may have the same outline as the enlarged or reduced projection image of the corresponding member. In this case, the interlocking relationship between the projection member and the corresponding member is adjusted as appropriate depending on the enlargement or reduction ratio.

In addition, the members (for example, the movable base projection members 6', 7') that correspond to the members (for example, the movable bases 6, 7) that are not likely to interfere with the lens barrel 1 or the objective lens 5, have the same outline as the projected image. It does not need to be formed.

Furthermore, a proximity sensor may be provided between the fixed end bracket 10 and the electrical stopper 12 instead of the contact switch.

Furthermore, the present invention can be applied to an apparatus in which a sample is placed near the center point of an objective lens in order to improve resolution.

As described in detail above, according to the sample moving device of the present invention, a sample is placed near the objective lens provided at the lower end of the lens barrel, and the sample is two-dimensionally moved in a direction intersecting the optical axis. A movable sample stand and a sample stand rotation drive mechanism capable of rotating the sample stand about a rotation axis perpendicular to the optical axis are provided, and the lens barrel and the sample stand are arranged on a plane orthogonal to the rotation axis. A first interference member having a similar shape to the projected image of the objective lens onto the above-mentioned plane, and a second interference member having a similar shape to the projected image of the sample onto the above-mentioned plane are formed, and the above-mentioned lens barrel and In order to prevent contact between the objective lens and the sample, an interference member moving mechanism is provided that moves the second interference member in the same manner as the projected image of the sample onto the plane in conjunction with the movement of the sample. At the same time, the second interference member moves and contacts the first interference member, thereby detecting the approach of the sample moving mechanism and the lens barrel and objective lens, and stopping the movement of the sample. The simple configuration with a detection section reliably prevents interference between the lens barrel and objective lens and the sample, which has the advantage of preventing damage to each part and greatly reducing the burden on the operator. There are advantages.

[Brief explanation of drawings]

Figures 1 to 4 show a conventional sample moving device. Figure 1 is a perspective view of its main parts, Figure 2 is a side view seen from the direction of the arrow in Figure 1, and Figure 3 is its sample stage. FIG. 4 is a schematic diagram for explaining the effect, and FIGS. 5 to 12 are schematic diagrams of a sample as an example of the present invention. Fig. 5 is a cross-sectional side view of the sample chamber wall, Fig. 6 is an enlarged cross-sectional view taken in the direction of - arrow in Fig. 5, and Fig. 7 is an enlarged sectional view of - in Fig. 6.
Figure 8 is a partial cross-sectional view along the arrow line.
Fig. 9 is an enlarged cross-sectional view in the direction of the - arrow in the figure; Fig. 9 is a cross-sectional view showing a modification thereof corresponding to Fig. 6;
Each figure is a side view showing a modified example of the fixed end bracket, and FIG. 12 is a side view showing another modified example corresponding to FIG. 5. 1... Lens barrel, 2... Sample chamber, 3... Sample stage,
3'...Sample stage projection member, 4...Sample, 4'...Sample projection member as a second interference member, 5...Objective lens, 5a...Lower bottom surface of the objective lens, 5b...
Objective lens side wall surface, 6, 7...Moving table, 6',
7'...Moving table projection member, 7a...Rail, 7'a
...Rail projection member, 8...Frame body, 8a...Rail, 8b...Rotating shaft, 8c...Rotating shaft support member,
9...Moving table, 9a...Rail, 10...Fixed end bracket, 10'...Mechanical stopper, 11...
...Spring, 12...Electric stopper as first interference member, 13...Contact type switch constituting the detection section, 14...High mesh seal, 15...Y
Directional movement transmission shaft, 15a...Keyway, 16...Rack, 17...Pinion, 18...Key pin, 1
9... Rack, 20... Pinion, 20a... Key, 21a, 21b... Screw, 22... Safety stopper, 23... Interference member support plate, 24... Vacuum holding plate, 25... Interference member group, 26... Projection image of the lens barrel and objective lens 5, M... Sample stage rotation drive mechanism, O... Optical axis (O axis), P, P'... Rotation axis 8b
plane orthogonal to

Claims (1)

[Claims] 1. A sample stage on which a sample is placed near the objective lens provided at the lower end of the lens barrel and capable of moving the sample two-dimensionally in a direction intersecting the optical axis, and a rotation axis perpendicular to the optical axis. a sample stage rotation drive mechanism capable of rotating the sample stage around the rotation axis, and a first image similar to the projected image of the lens barrel and objective lens on the plane, on a plane orthogonal to the rotation axis. and a second interference member having a similar shape to the projected image of the sample on the plane, and a second interference member having a similar shape to the projected image of the sample on the plane is formed, and the movement of the sample is An interference member moving mechanism is provided that moves the second interference member in the same manner as the projected image of the sample onto the plane, and the second interference member moves to
A sample moving device, comprising: a detecting section that detects the approach of the sample moving mechanism and the lens barrel and objective lens by contacting the interference member, and stops the movement of the sample.