JP3397490B2 - Stage moving mechanism - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage moving mechanism suitable for moving a material to be drawn or a sample in X and Y directions in an electron beam drawing apparatus or the like. . 2. Description of the Related Art FIGS. 1 and 2 show a mechanism for moving a material to be drawn, which has conventionally been used in an electron beam drawing apparatus or the like. FIG. 1 is a perspective view of the moving mechanism, and FIG. 2 is a plan view thereof. In the drawing, reference numeral 1 denotes a base placed at the bottom of a drawing chamber, for example, and a base 2 is mounted on the base 1. On the base 2, there is provided a stage 3 on which a wafer or a mask substrate, which is a material to be drawn, is placed, and the stage 3 is moved smoothly in the X and Y directions.
Many balls 4 are sandwiched between the base 2 and the stage 3. Here, the surface of the base 2 and the bottom surface of the stage 3 are processed and polished with good flatness, respectively.
Each ball 4 is selected such that the difference between the diameters is very small. With such a configuration, when the stage 3 moves, it is possible to keep the fluctuation of the vertical position of the stage 3 and the pitching / rolling extremely small. The arrangement of the balls 4 is maintained at a constant pitch by the retainer 5, and the weight of the retainer 5 is supported such that the bottom surface of the retainer 5 slides on the base 2. Further, a stopper 6 is provided around the base 2 so as to protrude therefrom.
Is designed so that it does not come off the base 2. The stage 3 is movable in the X and Y directions by being guided by a moving arm 7x in the X direction and a moving arm 7y in the Y direction. Two elongated center guides 8a and 8c are fixed to the arm 7y, and a center guide 8b is fixed to the stage 3 in the middle of the center guides 8a and 8c almost in parallel with them. FIG. 3A is a cross-sectional view taken along the line AA in FIG. 2, and FIG. 3B is a cross-sectional view of the cross section taken along a cross-sectional line BB of FIG.
Rollers 9 are sandwiched between the center guides 8a and 8b and between the center guides 8b and 8c. A retainer 10 is provided to maintain the position and posture of the roller 9, and the retainer 10 is movable with the roller 9. Although not shown, a center guide, a roller, and a retainer similar to those described above are provided between the arm 7x and the stage 3. A roller guide 11x is fixed to one end of the arm 7x. The arm 7x and the roller guide 11x are arranged so as to intersect at right angles. Ball screw 12x is part of roller guide 11x
Are screwed through, so that the ball screw 12
By rotating x, the roller guide 11x and the arm 7x fixed to the roller guide 11x are moved in parallel with the ball screw 12x. A roller is provided at the other end of the arm 7x, and the roller moves along a guide rail 13x arranged in parallel with the ball screw 12x. Similarly, a roller guide 11y is fixed to one end of the arm 7y, and the arm 7y and the roller guide 11y are arranged so as to intersect at right angles. A ball screw 12y penetrates a part of the roller guide 11y and is screwed. As a result, by rotating the ball screw 12y, the roller guide 11y is rotated.
y and the arm 7y fixed to the roller guide 11y
Is moved in parallel with the ball screw 12y. The other end of the arm 7y has a ball screw 12 similar to the arm 7x.
It moves along the guide rail 13y arranged in parallel with y. The ball screws 12x and 12y and the guide rails 13x and 13y are fixed to the base 1, and the ball screws 12x and 12y are fixed.
Is rotated by a motor 14x, and the ball screw 12
y is rotated by a motor 14y. In the above configuration, when the motor 14y is rotated, the ball screw 12y rotates, and as a result, the roller guide 11y moves in the Y direction. The arm 7y fixed to the roller guide 11y moves by the movement of the roller guide 11y. Accordingly, since the center guides 8a and 8c fixed to the arm 7y push the center guide 8b fixed to the stage 3 via the rollers 9 in the retainer 10, the stage 3 moves in the Y direction. Also,
When the motor 14x is rotated, the ball screw 12x rotates, and as a result, the roller guide 11x moves in the X direction. The arm 7x fixed to the roller guide 11x moves by the movement of the roller guide 11x. Therefore, the stage 3 moves in the X direction. At this time,
The center guide 8b moves together with the stage 3, and at the same time, the retainer 10 and the roller 9 also move in the X direction on the arm 7y which is a half of the movement of the stage 3. The movement of the stage 3 in the X and Y horizontal directions is performed smoothly because a large number of balls 4 are provided between the stage 3 and the base 2. [0009] With the above configuration, the ball 4
Is maintained on the upper surface of the base 2, but moves while sliding on the upper surface of the base 2 with the movement of the stage 3. With the weight of the retainer 5 applied to the upper surface of the base 2, the bottom surface of the retainer 5 and the base 2
Abrasion powder is generated from both. Since the plurality of balls 4 roll and pass over the same place on the surface of the base 2 where the wear powder is generated, the plurality of balls 4
Always gets on the wear powder. When this state occurs, the stage 3 is lifted, and the vertical position accuracy of the stage 3 deteriorates. Further, since the movement of the retainer 5 also has frictional resistance, if the movement of the stage 3 is repeated, the attitude (especially, the rotation direction) of the retainer 5 will be shifted, and the plurality of balls 4 will move with respect to the upper and lower base surfaces. Changes in the two-dimensional arrangement. This means that, by repeating the movement of the stage 3, the arrangement of the balls 4 is changed even at the same coordinate position, and the reproducibility of the vertical position accuracy of the stage 3 is also deteriorated. . Further, when the position of the retainer 5 shifts, the retainer 5 collides with a stopper 6 around the base 2, and depending on the moving direction of the stage 3, the retainer 5 may move.
The stopper 6 may move while being rubbed, and this phenomenon inevitably causes the generation of wear powder. The present invention has been made in view of the above points, and an object of the present invention is to minimize the generation of abrasion powder even when the stage is moved, thereby enabling precise stage movement. In order to realize a moving mechanism. According to a first aspect of the present invention, there is provided a stage moving mechanism, wherein a stage is arranged on a base and a plurality of balls are provided between an upper surface of the base and a bottom surface of the stage. In a moving mechanism that moves the stage smoothly on the base via the ball , a linear bearing is fixed to a retainer for regulating the ball arrangement.
And support this linear bearing with a shaft,
In addition, another linear bearing is fixed to both ends of the shaft
The linear bearing is supported by a shaft, and the retainer moves in the air between the bottom surface of the stage and the upper surface of the base without contacting the base surface. According to the first aspect of the present invention, a linear bearing is fixed to a retainer for regulating the arrangement of balls for smoothly moving the stage on the base.
Supported by the shaft, and at both ends of the shaft
Fix another linear bearing, this linear bearing
Is supported by the shaft, and is moved in the air between the bottom surface of the stage and the top surface of the base without bringing the retainer into contact with the base surface. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 4 is a plan view of a moving mechanism according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view along AA in FIG. In this embodiment, the same or similar components as those of the conventional example shown in FIGS. 1, 2 and 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. At four corners of the retainer 5, linear bearings 15x are fixed in parallel, and each linear bearing 15x is supported by two parallel shafts 16,17. At both ends of each of the two shafts 16 and 17, a linear bearing 15y is fixed in a direction orthogonal to the linear bearing 15x. The linear bearing 15y has two parallel shafts 18, 19
(Perpendicular to the shafts 16 and 17). The intermediate portion between the shafts 18 and 19 is fixed to the side surface of the base 2. With the above configuration, the weight of the retainer 5 is reduced by the linear bearings 15x and 15y to the shaft 16,
17, 18, and 19, there is no member other than the ball 4 to contact the upper surface of the base 2. Further, a stopper 20 is provided at each end of the shafts 16, 17, 18, and 19, so that even if the retainer 5 is displaced, the shaft 16,
Linear bearings 15x, 15y from 17, 18, 19
Is configured not to come off. When the sample stage 3 is moved in the X direction, a plurality of balls 4 sandwiched between the bottom surface of the sample stage 3 and the upper surface of the base 2 roll and move the retainer 5 to the X direction.
Try to move in the direction. At this time, the linear bearing 15x fixed to the retainer 5 is guided by the shafts 16 and 17, and the retainer 5 moves in the X direction together with the ball 4 without resistance. At this time, since the retainer 5 and the linear bearing 15x move in the air between the bottom surface of the sample stage 3 and the upper surface of the base 2, dust such as wear powder due to friction does not occur. Similarly, when the sample stage 3 moves in the Y direction, the plurality of balls 4 sandwiched between the bottom surface of the sample stage 3 and the plane of the base 2 roll and attempt to move the retainer 5 in the Y direction. At this time, the linear bearing 15x and the shafts 16, 17 fixed to the retainer 5 are moved in the Y direction. As a result, the linear bearing 15y fixed to both ends of the shafts 16 and 17 in the orthogonal direction is
It moves while being guided by the shafts 18 and 19. Therefore, the retainer 5 can move in the Y direction together with the ball 4 without resistance. At this time, retainer 5, linear bearing 1
5x and the shafts 16 and 17 move in the air between the bottom surface of the sample stage 3 and the plane of the base 2, and the linear bearing 15y moves outside the base 2, so that the stage 3
As in the case of the movement in the X direction, dust such as wear powder due to friction is not generated. Further, since two shafts 18 and 19 are fixed in the Y direction on the side surface of the base 2, the shafts 16 and 19 fixed in a direction orthogonal to the linear bearing 15y are provided.
17 can move in a state where a posture parallel to the X direction is maintained. Accordingly, since the retainer 5 does not shift in the rotation direction, the planar arrangement of the plurality of balls 4 with respect to the upper and lower base surfaces does not change. Although one embodiment of the present invention has been described in detail, the present invention is not limited to this embodiment. For example, although the movement of the stage in the electron beam writing apparatus has been mainly described, the present invention can be applied to other electron beam apparatuses such as a scanning electron microscope and an ion beam apparatus. Further, as the linear bearing and the shaft in the embodiment, a circulating linear bearing and a guide rail can be used as long as the guide is small and lightweight and has small running resistance. Further, four linear bearings are arranged at the four corners of the retainer. However, three or two linear bearings are possible as long as the retainer can maintain the posture. As described above, according to the first aspect of the present invention, the linear bearing is fixed to the retainer for regulating the arrangement of the balls for smoothly moving the stage on the base.
This linear bearing is supported by a shaft,
Also, fix another linear bearing on both ends of the shaft,
The linear bearing was supported by a shaft, and was moved in the air between the bottom surface of the stage and the top surface of the base without bringing the retainer into contact with the base surface. As a result, since there is nothing other than the ball in contact with the upper surface of the base, the retainer does not contact the base surface and moves in the air between the bottom surface of the stage and the upper surface of the base. Therefore, it is possible to eliminate the generation of dust such as wear powder due to the conventional friction. Therefore, since no dust is generated on the base surface, it is possible to prevent the ball from riding on the dust and deteriorating the accuracy of the vertical position of the stage. In addition, the sliding frictional resistance between the retainer and the base surface is eliminated, and the rolling resistance between the linear bearing and the shaft is reduced. Therefore, the traveling resistance of the movement of the retainer is reduced, and the occurrence of the displacement of the retainer can be eliminated. Further, since the linear bearing and the shaft supporting the retainer do not rotate in the horizontal direction but move in the X-Y direction, the retainer does not shift in the rotational direction. Therefore, even if the stage movement is repeated, the arrangement of the balls at the same coordinate position does not change, so that the reproducibility of the vertical movement of the stage can be improved. Further, even if the retainer is displaced and the linear bearings hit the stoppers at both ends of the shaft,
Since the structure is such that the retainer and the stopper come into contact only from one direction, the retainer and the stopper do not move while rubbing as in the related art, and the generation of dust due to this can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a conventional stage moving mechanism. FIG. 2 is a plan view of the moving mechanism shown in FIG. FIG. 3 is a diagram showing a structure of a roller and a retainer provided between center guides for moving a stage. FIG. 4 is a plan view of a stage moving mechanism according to an embodiment of the present invention. 5 is a sectional view of the stage moving mechanism shown in FIG. [Description of Signs] 2 Base 3 Stage 4 Ball 5 Retainer 7x, 7y Arm 15x, 15y Linear bearing 16, 17, 18, 19 Shaft

Claims (1)

(57) [Claim 1] A stage is arranged on a base, and a plurality of balls are provided between an upper surface of the base and a bottom surface of the stage, and the stage is smoothly moved on the base via the balls. In a moving mechanism that moves the ball, a linear bearing is fixed to a retainer for regulating the arrangement of balls, this linear bearing is supported by a shaft, and another linear bearing is fixed to both ends of the shaft,
A stage moving mechanism in which the linear bearing is supported by a shaft and the retainer moves in the air between the bottom surface of the stage and the upper surface of the base without contacting the base surface.