JP2002098230A - Vacuum sealing mechanism of column stage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow simple assembling by eliminating necessity for any adjusting operation for a crushing margin of an O-ring (vacuum seal). SOLUTION: A sealing plate 51 is installed on a base 11 on the side nearer a vacuum chamber than a stage 13 on which a column 19 is supported and moved, and thereon 51 a sliding plate 52 is mounted through an X-Y guide 53, and the column 19 is inserted through the center hole 54 therein. O-ring is interposed in a sealing plate mounting part (a), and O-rings 55 and 58 are set between the mating parts of the center hole 54 and column 19 and between the confronting surfaces of the sealing plate 51 and sliding plate 52. A vacuum seal mechanism is provided independently of the stage 13 to allow the setting of the O-ring crushing margin to be executed simply and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for using an electron beam in a vacuum, such as an electron beam tester or an electron beam processing machine, for supporting a column containing an electron gun for emitting an electron beam or an optical system. In particular, the present invention relates to a vacuum sealing mechanism for moving the column stage.

[0002]

2. Description of the Related Art The structure of a conventional column stage of this type will be described with reference to FIG. The base 11 has a rectangular opening 12 formed in the center to form a rectangular frame shape, and can be moved on the base 11 in two orthogonal directions (X, Y directions) in a plane parallel to the base opening surface. A stage 13 is mounted so as to cover the opening 12. In this example, the stage 13 has a pair of X guides 14, a pair of Y guides 15, an X plate 16 having a rectangular frame shape, and a mounting hole 17 in the center.
And a rectangular Y plate 18 on which is formed.

[0003] Although the X guide 14 and the Y guide 15 are shown in a simplified form in the figure, they are each configured so that a pair of rail-shaped members are movably engaged via bearings. The other rail-shaped member is movable in its extending direction. The X plate 16 is mounted on the base 11 via an X guide 14 installed on two opposing sides of the base 11 so as to be movable in the X direction, and the Y plate 18 is installed on two opposing sides of the X plate 16. It is located in the frame of the X plate 16 via the Y guide 15 and is movable in the Y direction.

A column 19 is mounted in a mounting hole 17 of a Y plate 18. The axis of the column 19 is perpendicular to the opening surface of the base 11, that is, in the Z-axis direction, and the one end for emitting the electron beam is inserted into the mounting hole 17 so as to face the opening 12 of the base 11. Supported on plate 18. The base 11 is mounted on a vacuum chamber 21 having an open upper surface, whereby a column 19 is opened.
Has one end located in a vacuum.

In order to vacuum seal the column 19, the base 1
As shown in FIG. 1, a frame-shaped base plate 22 is attached to 1 so as to protrude over the entire inner circumference thereof, and an O-ring 23 is provided between opposing plate surfaces of the base plate 22 and the Y plate 18. Placed and vacuum sealed. In the drawing, reference numeral 24 denotes a groove in which the O-ring 23 is arranged.
In FIG. 3, although not shown in the drawing, the O-ring is interposed between the fixing portions a and b, which are indicated by alternate long and short dash lines, and are vacuum-sealed, and the base 11 is connected to the vacuum chamber 21. An O-ring is also interposed in the mounting portion c so as to be vacuum-sealed.

FIG. 4 shows an electron beam tester (EB tester) provided with the column stage 25 having the above structure.
1 schematically shows the structure of the main body 2 in the figure.
Reference numeral 7 denotes a test head. The base 11 is supported on the main body 26 via an arm 28. The arm 28 can be moved up and down, and the base 11 is mounted on the vacuum chamber 21 by lowering the arm 28. The electric unit 31 and the vacuum pump 32 are mounted on the base 11.

[0007]

Meanwhile, in the column stage 25 having the above-described structure and mounted on the vacuum chamber 21, the column stage 25 is disposed between the opposing plate surfaces of the base plate 22 and the Y plate 18. O-ring 23
It is a very important element in terms of function. That is,
In performing vacuum sealing, it is sufficient to secure a crushing allowance of a predetermined amount or more. However, with an increase in the crushing allowance, the frictional force between the Y plate 18 and the O-ring 23 increases. Is impaired, that is, stage 13
In this case, the XY movement of the O-ring 23 becomes abnormal or impossible, so that the O-ring 23 is required to have extremely high accuracy for the crushing.

[0008] The crushing allowance of the O-ring 23 includes a base plate 22, a base 11, an X plate 16, and a Y plate 18.
Therefore, depending on the accumulation of the dimensional tolerance of each component and the deflection of each component, conventionally, it has been performed to adjust the crushing allowance based on the result of the dimensional confirmation during the assembly and the operation confirmation after the assembly. The adjustment of the crushing allowance of the O-ring 23 is performed by adjusting (selecting) the thickness of the shim so that the shim 33 is interposed in the mounting portion of the Y plate 18 with respect to the Y guide 15. For this reason, reassembly is always required, and in this regard, the assembling work is troublesome and troublesome.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a vacuum seal mechanism for a column stage which can eliminate the need for adjusting the crushing amount of an O-ring (vacuum seal) and can be easily assembled. To provide.

[0010]

According to the present invention, a frame-shaped base having an opening formed in the center, and a base mounted on the base so as to cover the opening and parallel to the base opening surface. A stage movable in two orthogonal directions, and a column whose axis is perpendicular to the opening surface and which is supported by being inserted into the stage so that one end faces the opening, and the upper surface is open. A vacuum seal mechanism in a column stage in which a base is mounted on a vacuum chamber and one end of a column is located in a vacuum protrudes over the entire inner circumference of the base on the vacuum chamber side from the stage. A sliding plate having a central hole through a guide that allows movement in the above two directions is mounted on a ceiling plate having a frame shape as described above. With the one end side of the column inserted through the center hole, the mounting portion of the sealing plate to the base, the inner peripheral surface of the center hole and the opposite portion of the column and the sealing plate on the axis side from the guide and An O-ring is arranged between the sliding plate and the facing plate surface to perform vacuum sealing.

[0011]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an embodiment of the present invention, and portions corresponding to those in FIG. 3 are denoted by the same reference numerals. In this example, the stage 13 that is mounted on the base 11 to support the column 19 and enable the XY movement thereof is constituted by an XY guide 41 and a plate 42. The XY guide 4 in FIG.
1 is simplified.

FIG. 2 shows an outline of the structure of the XY guide 41. The XY guide 41 is moved to a block 45 having grooves 43, 44 formed on the upper and lower surfaces in directions perpendicular to each other and to the grooves 43, 44, respectively. Rail 4 freely engaged
6, 47, and these rails 46, 4
7 are attached and fixed to the base 11 and the plate 42, respectively. The XY guides 41 are arranged on four sides of the base 11 having a rectangular frame shape,
The plate 42 is supported by two XY guides 41 so as to be XY movable.

On the other hand, in order to vacuum seal the column 19, in this example, as shown in FIG.
, A sliding plate 52, an XY guide 53, and a required O-ring are arranged. The sealing plate 51 is formed in a frame shape, and as shown in FIG.
On the vacuum chamber side, it is attached to the base 11 so as to protrude over the entire inner circumference thereof. Although not shown in the drawing, an O-ring is interposed at the mounting portion (fixing portion) a shown by a dashed line in the drawing, and is vacuum-sealed.

The sliding plate 52 is mounted on the sealing plate 51 via an XY guide 53 with its plate surface parallel to the sealing plate 51 and
The X guide is applied to the sealing plate 51 by the Y guide 53.
Y movement is enabled. The XY guide 53 has the same structure as the XY guide 41 described above, and is arranged on each of four sides of the sealing plate 51. The sliding plate 52 has a hole 5 at its center.
4 are formed, and one end of the column 19 is inserted into the central hole 54. An O-ring 55 is interposed between the inner peripheral surface of the opposed central hole 54 and the peripheral surface of the column 19 (the peripheral surface protruding like a flange in this example) and vacuum-sealed. In the drawing, reference numeral 56 denotes an arrangement groove for the O-ring 55.

On the other hand, a groove 57 is formed around the axis of the column 19 on the plate surface of the sealing plate 51 on the axis side of the column 19 with respect to the XY guide 53.
A ring 58 is arranged, and the space between the sealing plate 51 and the sliding plate 52 is vacuum-sealed. According to the above-described structure, the column 19 is supported by the plate 42 and is moved XY by the XY guide 41. With this movement, the sliding plate 52 mounted on the XY guide 53 also moves. Has become.

That is, in this example, the column 19 is vacuum-sealed by a vacuum sealing mechanism composed of a sealing plate 51, a sliding plate 52, an XY guide 53, O-rings 55 and 58, and O-rings arranged at the mounting portion a. The vacuum sealing mechanism supports the column 19,
It has an independent configuration separate from the stage 13 to be moved. Such a vacuum seal mechanism forms a so-called floating mechanism for the column 19,
It is not affected by the weight of the column 19,
Therefore, the bending caused by the column 19 does not occur. Hereinafter, the crushing allowance of each O-ring will be described.

The O-ring 58 can be compressed by reducing the depth of the groove 57 of the sealing plate 51 and the dimension (height) of the XY guide 53. The deflection generated in the sealing plate 51 and the sliding plate 52 is also reduced by the column 19 and the stage. Since it is unrelated to 13 and can be predicted in advance, that is, before incorporating it into the column stage,
The required squeeze allowance can be easily set to the sliding plate 52 without giving a frictional force that hinders the movement thereof. For example, there is no need to adjust the squeeze allowance with a shim or the like as in the related art. Becomes

Since the O-ring 55 and the O-ring of the mounting portion a are both disposed on the fixed portion, it is sufficient to secure a predetermined amount of crushing allowance, and fine adjustment of the crushing allowance is unnecessary. The O-ring 55 can be crushed by reducing the diameter of the central hole 54 of the sliding plate 52 and the diameter of the groove 56 of the column 19, and the sliding plate 52 can be moved XY so that the central hole 54 is concentric with the column 19. And the sliding plate 5
Since the positional accuracy of the column 19 in the Z direction with respect to 2 does not affect the crushing allowance, it does not depend on the relative positional accuracy (assembly accuracy) between the column 19 and the sliding plate 52.

[0019]

As described above, according to the present invention, by setting the vacuum sealing mechanism independent of the stage for supporting and moving the column, the setting of the O-ring (vacuum seal) can be set. This can be performed easily and accurately, and thus it is possible to eliminate the need for a troublesome work requiring disassembly and reassembly, such as adjusting the crushing allowance of the O-ring by adjusting the shim thickness as in the related art.

Therefore, according to the present invention, the assembling work of the movable column stage while vacuum sealing the column can be performed very easily.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention.

FIG. 2 is a schematic perspective view of an XY guide 41 in FIG.

FIG. 3 is a diagram for explaining a conventional column stage vacuum sealing mechanism.

FIG. 4 is a diagram for explaining a schematic configuration of an electron beam tester.

Claims (1)

[Claims] 1. A frame-shaped base having an opening formed in the center, and mounted on the base so as to cover the opening so as to be movable in two orthogonal directions in a plane parallel to the base opening surface. A stage and a column having an axis perpendicular to the opening surface and a column inserted and supported by the stage so that one end faces the opening, and the base is mounted on a vacuum chamber having an open upper surface. A vacuum seal mechanism in a column stage in which one end side of the column is located in a vacuum, wherein on the vacuum chamber side from the stage, the base protrudes over the entire inner circumference thereof. A frame-shaped sealing plate is attached to the sliding plate, and a sliding hole with a central hole is provided on the sealing plate via a guide that enables movement in the two directions. The mounted, in its central bore is inserted one end of the column, attachment to the base of the sealing plates,
O-rings are arranged between the opposing portions of the inner peripheral surface of the central hole and the column and the opposing plate surfaces of the sealing plate and the sliding plate on the axial center side of the guide, and are vacuum-sealed. Vacuum sealing mechanism for column stage.