JPS64781B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a sample exchange device in a vacuum apparatus such as an electron beam exposure apparatus.

[Prior art]

In electron beam exposure equipment that requires ultra-high vacuum, such as electron beam exposure equipment, it is necessary to introduce the sample into the vacuum from the atmosphere side and replace it, but O-ring packing cannot be used as a vacuum seal. To transmit the force from the atmosphere to the sample exchange rod in vacuum, metal bellows or magnetic coupling force is used. Normally, in such a sample exchange device, a small force is sufficient when moving the exchange rod forward or backward, but a large force is required when attaching and detaching the sample holder in the final stage from the sample stage. When using the binding force of a magnet, it is necessary to obtain a magnetic binding force that is commensurate with the required output in the final stage, which has the disadvantage of increasing the size of the device.

[Purpose of the invention]

This invention is intended to improve the above-mentioned conventional drawbacks.
The yoke attached to the exchange rod is fixed to an axial bearing, the magnet is rotated, and the rotational force of the exchange rod is decelerated and converted into the thrust force of the sample holder, making it possible to attach and detach the sample holder with a small magnetic circuit. Therefore, it is an object of the present invention to provide a sample exchange device for a vacuum device, which allows the device to be made smaller.

[Structure of the invention]

The present invention provides an exchange rod that moves axially within a casing to move the sample holder forward and backward; an axial bearing that allows the exchange rod to move in the axial direction and is rotatably supported by a fixed bearing; a yoke fixed to the exchange rod; a magnet that is movable in the axial direction along the outer periphery of the casing so as to form a magnetic path with the yoke and is rotatable along the outer periphery in an advanced position; and a sample holder. a clutch that secures the yoke to an axial bearing in a removable position;
A sample exchange device for a vacuum apparatus is characterized in that it is equipped with a mechanism that converts the rotational force of the exchange rod into a sample holder thrust force in a decelerating manner.

[Embodiments of the invention]

The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 is an exploded perspective view showing an outline of a sample exchanging device according to an embodiment of the present invention, with a part thereof shown in cross section, FIG. 2 is a sectional view of the main part thereof, and FIG.
A sectional view, and FIG. 4 is a BB sectional view.

In the drawing, 1 is a sample chamber, and sample stage 2
is provided so that it can move in the X direction and the Y direction. The sample stage 2 is provided with a pedestal 3, and the engaging portion 6 of the sample holder 5 is inserted into the dovetail groove 4 from the guide portion 7. The sample holder 5 holds a sample 8 on the top surface and has a screw hole 9 on the rear surface. A sample exchange chamber 12 having a gate valve 10 and an exhaust port 11 is connected to the sample chamber 1, and a casing 14 is attached to a removable lid 13 of the sample exchange chamber 12.

An exchange rod 15 that moves in the axial direction is provided in the casing 14, and has a threaded portion 16 at its tip that is screwed into the screw hole 9, so that the sample holder 5 can be moved from the sample exchange chamber 12 to the attachment/detachment position of the sample chamber 1. It is designed to move forward or backward. The exchange rod 15 is supported in the front part of the casing 14 by an axial bearing 18 having a plurality of bearings 17 in the axial direction so as to be movable in the axial direction. The axial bearing 18 has a housing 19 rotatably supported by a fixed bearing 21 having a circumferential bearing 20, and a hook portion 19a is formed at the rear of the housing 19. The rear part of the exchange rod 15 is rotatably supported via a bearing 24 on a movable bearing 23 that is movable in the axial direction by a plurality of rollers 22 .

The yoke 25 is attached to the screw 25 adjacent to the moving bearing 23.
The yoke 25 is attached to the exchange rod 15 by a, and a hook 25b is formed at the front of the yoke 25.
At the forward position 25c of the yoke 25, a clutch 26 is arranged on the outer periphery of the position where the hook parts 19a and 25b overlap, and the clutch 26
are connected in the thrust direction. The clutch 26 is connected to the casing 4 by a bellows 27.
The shaft 28 is supported by a shaft 28, an outer ring 29 is attached to the shaft 28, and an inner ring 31 is rotatably attached to the outer ring 29 via a bearing 30. , 25b are tightly held together and have a U-shaped cross section.

The yokes 34 and 34 are movable in the axial direction along the outer circumference of the casing 14 by guides 32 and 33 provided on both sides of the outer circumference of the rear half of the casing 14.
35 is provided, and horseshoe-shaped magnets 36, 3 are provided on both sides thereof.
7 are connected to form a magnetic path through the yoke 25. 38 is a line of magnetic force, and 39 is a metal fitting for fixing the yoke 34 and the horseshoe-shaped magnets 36, 37. The yokes 34, 35 and the magnets 36, 37 move in a coupled state, and the guides 32, 33 have a shape in which the front half portions are omitted so that they can rotate along the outer periphery of the casing 14 at the forward position 34a.

In the sample exchanger configured as described above, when the yokes 34, 35 and the magnets 36, 37 are advanced along the guides 32, 33 from the position shown in FIG. According to this, the inside of the casing 4 is advanced. At this time, the movable bearing 23 is moved in the axial direction by the roller 22, and since the exchange rod 15 is supported by this, it slides on the axial bearing 18 and moves forward. When the yoke 25 moves forward to the forward position 25c, the sample holder 5 screwed to the tip of the exchange rod 15 moves into the sample exchange chamber 1.
2 to the attachment/detachment position of the sample chamber 1, and the guide part 7
is inserted into the dovetail groove 4.

In this state, the yoke 34 advances to the forward position 34a and reaches a position where it is removed from the front end portions of the guides 32, 33, and the hook portion 25b of the yoke 25 moves forward to the forward position 34a.
5c overlaps with the hook part 19a of the housing 19, so when the shaft 28 of the clutch 26 is pushed to eccentrically make the outer ring 29 and the inner ring 31, the inner ring 31 grabs the hook parts 19a and 25b in a superposed state and moves in the thrust direction. join to. From this state, when the yokes 34, 35 and the magnets 36, 37 are rotated around the outer periphery of the casing 14 along the front ends of the guides 32, 33 (rotated counterclockwise if the threaded portion 16 is right-handed), the yokes 25 and axial direction Bearing 18
At the same time, the replacement rod 15 replaces the bearings 20 and 24.
It is supported by and rotates. At this time, the exchange rod 15 rotates in the fixed position in the axial direction, and the rotation of the sample holder 5 is restricted by the pedestal 3, so the rotational force is converted into a decelerating thrust by the threaded portion 16. The screwed sample holder 5 is advanced in the axial direction.
In this way, the engaging portion 6 is inserted into the dovetail groove 4, and the sample holder 5 is attached to the sample stage 2.

The relational expression regarding the force at this time is as follows.

F: Force acting in the circumferential direction at the center of the thread Q: Axial force α: Pitch angle of the thread 2β: Angle of the thread μ: Coefficient of friction of the thread Fm・L=F・r+Q・ra×μa ...(2) Fm: Magnetic coupling force L: Arm length of the moment of magnetic coupling force ra: Average radius of the bearing that supports the thrust μa: Friction coefficient of the bearing that supports the thrust r: Average radius of the thread In this way, an output in the axial direction that is sufficiently larger than the magnetic coupling force can be obtained, and the sample holder 5 can be mounted on the sample stage 2 using a small magnetic circuit. Place the sample holder 5 on the sample stage 2.
When attaching and detaching from the holder, the operation can be done in the reverse order.

In the above description, a screw was used as a mechanism for converting rotational force into a decelerating thrust, but a ball screw, bayonet, or other mechanism may be used. Further, the magnetic circuit, bearing, clutch, etc. are not limited to those shown in the drawings, and may have other structures. Furthermore, the present invention is applicable not only to electron beam exposure apparatuses but also to sample exchange apparatuses of other vacuum apparatuses.

〔Effect of the invention〕

According to this invention, in a sample exchange device that utilizes the binding force of a magnet, when a sample holder is attached or detached, the yoke attached to the exchange rod is fixed to an axial bearing, the magnet is rotated, and the rotational force of the exchange rod is transferred. Since the sample holder is attached and detached by converting it into thrust in a decelerated manner, it is possible to obtain an axial thrust that is larger than the magnetic coupling force.This makes it possible to attach and detach the sample holder using a small magnetic circuit, and the device can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an outline of a sample exchanging device according to an embodiment of the present invention, with a part thereof shown in cross section, FIG. 2 is a sectional view of the main part thereof, and FIG.
A sectional view, and FIG. 4 is a BB sectional view. In each figure, the same symbols indicate the same parts, 1 is the sample chamber, 2 is the sample stage, 3 is the pedestal, 4 is the dovetail groove,
5 is a sample holder, 9 is a screw hole, 12 is a sample exchange chamber, 14 is a casing, 15 is an exchange rod, 16 is a threaded portion, 18 is an axial bearing, 21 is a fixed bearing, 23
25, 34, 35 are yokes, 26 are clutches, 32, 33 are guides, and 36, 37 are magnets.

Claims (1)

[Claims] 1. An exchange rod that moves axially within the casing to move the sample holder forward and backward, and an axial bearing that allows the exchange rod to move in the axial direction and is rotatably supported by a fixed bearing. a yoke fixed to the exchange rod; and a magnet that is provided to move in the axial direction along the outer periphery of the casing and to be rotatable along the outer periphery in the forward position so as to form a magnetic path with the yoke. , a sample exchange of a vacuum apparatus characterized by comprising a clutch for fixing the yoke to an axial bearing at a sample holder attachment/detachment position, and a mechanism for converting the rotational force of the exchange rod into a thrust force of the sample holder in a decelerating manner. Device. 2. A sample exchange device for a vacuum apparatus according to claim 1, wherein the exchange rod is supported at the rear by a moving bearing. 3. A sample exchange device for a vacuum apparatus according to claim 1 or 2, wherein the magnet is connected to a yoke that moves along a guide provided on the outer periphery of the casing. 4. A sample exchange device for a vacuum apparatus according to any one of claims 1 to 3, wherein the clutch connects the axial bearing and the hook portion of the yoke in a thrust direction in a superposed state. 5. A sample exchange device for a vacuum apparatus according to any one of claims 1 to 4, wherein the mechanism for converting thrust into thrust is a screw, a ball screw, or a bayonet.