KR101470749B1 - Ultraprecision and long displacement stage - Google Patents

Abstract

The present invention relates to a high-precision long-displacement nano stage including a base plate where an object is placed, an X axis base that has an LM guide and a linear motor to drive the base plate in an X axis direction, and a Y axis base that has an LM guide and a linear motor to drive the base plate in an Y axis direction. Friction pads having friction resistance during sliding driving are provided to act on the X axis base and the Y axis base and the X axis base and the Y axis base have a slide bar corresponding to the sliding driving and a physic instrumente (PI) motor transmitting a driving force to the slide bar. The PI motor has a control unit receives a value of an interferometer detecting the amount of movement of the base plate and feedbacks the value for driving control.

Description

[0002] Ultraprecision and long displacement stage [0003]

The present invention relates to a high-precision large-displacement nano-stage, and more particularly, to a nano-stage capable of performing precise transfer and compensating for an error value to drive a high-precision stage.

In general, ultra-precision measurement technology and process control technology at the nanometer level can measure the shape of high-precision parts such as optical parts in a short time, measure the mask line width in ultra-high density semiconductor processing, and fine- , And the like.

Examples of devices related to the nano-device technology include a focused ion beam (FIB) device and a scanning electron microscope (SEM) device, and a stage for finely controlling the position of a target material.

Korean Patent Laid-Open Publication No. 2003-0033744 discloses an ultrafine position control technique using a laser. The disclosed position control technique uses an AC servomotor and a lead screw system for high-speed, large-stroke movement of the ultra-precision positioning mechanism, and a piezo actuator is used for finer movement. The displacement feedback is measured using a laser interferometer and feedback is provided in real time.

The fine control technology has a structure in which a fine positioning mechanism using a piezo actuator is provided on the upper portion of a high-speed / large-stroke positioning mechanism using a feed screw mechanism, and each of the positioning mechanisms is driven independently, It is difficult to realize a precise micro displacement movement of the positioning mechanism, and each scale has to be provided in order to measure the displacement of each positioning mechanism. That is, since the large-stroke positioning mechanism and the fine positioning mechanism are independent driving systems, a system for feedback control of displacement must be provided for each positioning mechanism. However, in order to construct a feedback control system for the fine positioning mechanism, The displacement of only the large-stroke positioning mechanism is feedback-controlled using the laser interferometer. However, in the case of the piezo actuator constituting the fine positioning mechanism, a large number of So that it is difficult to realize precise minute displacement as a compact structure.

On the other hand, there is a stepper capable of precise minute displacement movement with respect to the whole area, but usually, the stepper uses an air guide, which is difficult to apply to a vacuum atmosphere.

In order to solve such a problem, FIG. 1 is a view schematically showing a conventional large-sized nano-stage. In the drawing, the upper plate of the stage is constituted by an LM guide (slider) and is connected to a ball screw, and is transported on a large side by driving of the motor, and stops at a predetermined position value. In addition, it compensates for the error of the precision of the ball screw by the error by using the piezo motor.

However, in such a conventional technique, if the ball screw has a machining tolerance of 500 mm in the case of a precision grade (C0 to C1 grade), shaking in an axial direction of about 50 μm occurs, and a PI motor is applied as a piezoelectric actuator to a predetermined position Move it to stop. At this time, the movement of the stage appears to have no motion when viewed from the eyes, but drift occurs. Confirmation of drift is evident in electron microscopy and high magnification devices.

Further, if the positioning is performed using only the piezo motor, it takes a long time for the positioning due to the influence of the drift and the ball screw, and it is difficult to know the reference point and displacement about the position when the stage is stopped in the predetermined position range.

In order to solve such a problem, a nanostage according to the prior art shown in FIGS. 1 and 2 is shown. A platform, an X-axis driver, a Y-axis driver, a position detector, and a motion controller. In other words, the X-axis support plate 210, the rail 211, and the fixing blocks 212 and 213 are provided. The X-axis ball screw 220 and the X-axis drive motor 230, An X axis slider 240 and an X axis piezo actuator 250 and a preloader 260 for driving and controlling the X axis ball screw for precise control.

However, such a conventional high-precision stage suffers from a serious problem of drift phenomenon. In particular, the application of the ball screw system has a disadvantage that it is difficult to apply a driving error range according to processing variation in a high-precision industrial.

KR 10-2003-0033744 KR 10-0663939

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to provide a reliable nano-stage as a result of ensuring more precise driving and correcting functions for drift.

It is another object of the present invention to provide a high-precision nano-scale stage capable of eliminating a reduction in accuracy due to a variation in machining tolerance of a part.

According to an aspect of the present invention, there is provided an apparatus for driving a base plate, including: a base plate on which an object is placed; an X-axis base including an LM guide and a linear motor for driving the base plate in the X- And a Y-axis base including an LM guide and a linear motor (Liner Moter) for driving the plate in the Y-axis direction. The X-axis base and the Y-axis base include friction pads And a piezoelectric actuator for applying pressure to the friction pad.

The X-axis base and the Y-axis base further include a linear scale for detecting a movement amount.

In addition, the friction pad includes two friction pads on both sides of the X-axis base and the Y-axis base.

The X-axis base and the Y-axis base are each provided with two friction pads on the inside of the LM guide formed on both sides in order to guide the sliding drive according to the driving force of the linear motor.

The X-axis base includes a linear motor provided on one side of a base having a predetermined size, an LM guide provided on the base and slidably supporting both sides of a lower surface of the base plate positioned on the upper side, A friction pad provided on both sides in the inner direction of the LM guide, and a linear scale positioned at the center for detecting a movement amount of the base plate.

The Y-axis base includes a linear motor provided on one side of a base having a predetermined size, an LM guide provided on the base and slidably supporting both sides of the lower surface of the X-axis base located on the upper side, A friction pad provided on both sides in the inner direction of the LM guide, and a linear scale located at the center for detecting the movement amount of the X-axis base.

Also, the high-precision large-displacement nano stage may include a controller for receiving a value of an interferometer for detecting a movement amount of the base plate, and feeding back the value to control driving.

The present invention, which is constructed and operated as described above, is characterized by being capable of quick and accurate movement and capable of correcting for drift.

In addition, there is no deviation from the machining tolerance generated in the manufacture of the ball screw, and an absolute reference value and a deviation can be confirmed on the stage while using an interferometer.

Fig. 1 is a schematic diagram of a nanostage according to the prior art,
FIG. 2 is a detailed view of the driving unit of FIG. 1,
FIG. 3 is a schematic configuration diagram of a high-precision large-displacement nano stage according to the present invention,
4 is a detailed view showing an X-axis base of the high-precision large-displacement nano stage according to the present invention,
5 is a detailed view showing a Y-axis base of a high-precision large-displacement nano stage according to the present invention,
6 is a side view of a base constructed in accordance with the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a large displacement nano stage according to the present invention will be described in detail with reference to the accompanying drawings.

The large-sized nano-stage according to the present invention includes a base plate on which an object is placed, an X-axis base including an LM guide and a linear motor for driving the base plate in the X-axis direction, Axis base and a Y-axis base including an LM guide and a linear motor (Liner Moter) for driving in the Y-axis direction. The X-axis base and the Y-axis base include friction pads having frictional resistance during sliding operation, And a piezoelectric actuator for applying pressure to the pad.

The high-precision nano-stage according to the present invention comprises a friction pad and a PI motor, each of which is provided on an X-axis base and a Y-axis base to perform braking control during sliding operation of a stage, To provide a large-displacement nano-stage capable of high-precision drive control by feeding back the amount of movement through the nano-scale.

FIG. 3 is a schematic configuration diagram of a high-precision large-displacement nano stage according to the present invention.

The present invention basically comprises a base plate (40) for positioning an object, an X-axis base (10) for controlling the sliding motion of the plate in the X-axis direction, an X-axis base And an LM scale including a linear motor and an LM guide respectively configured on the X-axis base and the Y-axis base, and a movement amount counting unit.
Further, friction pads (13, 23) provided respectively in the X-axis base (10) and the Y-axis base (20) corresponding to the main technical concept of the present invention to determine drift compensation and precision drive, (Physic Instrumente) motors 12 and 22, respectively.

delete

Basically, the large-sized nano stage is provided with an X-axis base and a Y-axis base, respectively. Each base realizes X-axis and Y-axis driving through a driving means. Here, the LM guide is coupled for sliding driving, Lt; / RTI > In the case of the driving means, a device such as a ball screw or a linear motor can be applied. In the present invention, the linear motor 30 is applied.

A Y-axis base for driving the X-axis base in the Y-axis direction supports the Y-axis base, an X-axis base for driving the base plate in the X- .

Meanwhile, the present invention is equipped with an interferometer (50) for accurately detecting the movement amount of the stage, that is, accurately detecting the movement amount of the base plate. The interferometer is a well-known apparatus and can detect the amount of movement using an optical signal. Here, the detected signal is applied as a feedback value for PI motor control.

FIG. 4 is a detailed view showing an X-axis base of a high-precision large-displacement nano stage according to the present invention, and FIG. 5 is a detailed view showing a Y-axis base of a high-

As shown in FIGS. 3 and 4, LM guides 11 and 21 for guiding slide driving are disposed on both sides of the base, and friction pads 13 and 23 are provided on the side surfaces of the LM guide, respectively. The position of the friction pad is applied by way of example and can be configured in a separate slide bar.

Fig. 6 is a side view of the X-axis base constructed in accordance with the present invention (the Y-axis base is correspondingly omitted).

The friction pads provided on the X-axis base act as braking members when the PI motors 12 and 22 as the piezoelectric actuators are rubbed to act as a braking member. As described above, the friction pads provided on the X axis base are fed back to the PI driving unit , The PI motor is braked by applying pressure (resistance) to the friction pad. At this time, the PI motor maintains a state of being in contact with the friction pad at all times, and acts to apply a greater pressure during driving to help accurately determine the stop position.

Therefore, the piezoelectric actuators, that is, the PI motors and the friction pads significantly reduce the drift phenomenon, thereby enabling more precise driving and stopping.

 Similarly, the Y-axis base is provided with a friction pad and a PI motor, respectively, to compensate for the drift phenomenon corresponding to the Y-axis drive.

On the other hand, in the present invention, a separate linear scale is additionally provided in order to detect a drive value, that is, a movement value driven by the linear motor of each axis, on the base of the X and Y axes.

Although not shown in the drawing, a driving driver for controlling the linear motor and a driving driver for driving the PI motor are respectively configured. The stage is generally controlled, and a detection signal detected by the interferometer is received to apply a control signal to the driving driver And a control unit.

According to the present invention configured as above, the PI motor and the friction pad capable of compensating drift with respect to the X-axis driving base and the Y-axis driving base can be driven with high precision, and the PI motor feeds back the signal detected by the interferometer It is possible to realize a very accurate stage by controlling it and it is suitable for high precision industry.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. On the contrary, those skilled in the art will appreciate that many modifications and variations of the present invention are possible without departing from the spirit and scope of the appended claims. And all such modifications and changes as fall within the scope of the present invention are therefore to be regarded as being within the scope of the present invention.

10: X-axis base
11: LM Guide
12: PI motor
13: Friction pad
14: Linear scale
20: Y-axis base
21: LM Guide
22: Piezoelectric actuator (PI motor)
23: Friction pad
30: Linear motor
40: base plate
50: Interferometer

Claims (7)

A base plate (40) on which the object is placed;
An X-axis base 10 including an LM guide and a linear motor 30 for driving the base plate 40 in the X-axis direction;
A Y axis base 20 including an LM guide 11 and a linear motor 30 for driving the base plate 40 in the Y axis direction,
Two friction pads 13 and 23 having frictional resistance during sliding operation are provided on both sides of the X axis base 10 and the Y axis base 20 and a piezoelectric actuator 12 22). ≪ / RTI > The method according to claim 1,
Wherein the X-axis base and the Y-axis base further comprise a linear scale for detecting a movement amount. delete 2. The X-ray tube according to claim 1, wherein the X-axis base and the Y-
Wherein two friction pads are respectively provided inside the LM guide formed on both sides in order to guide the sliding movement according to the driving force of the linear motor. 2. The X-ray machining system according to claim 1, wherein the X-
A linear motor provided on one side of a base of a predetermined size;
An LM guide provided on the base and slidably supporting both sides of the lower surface of the base plate positioned on the upper side;
A friction pad provided on both sides in the inner direction of the LM guide formed on both sides; And
And a linear scale located at the center for detecting a movement amount of the base plate. 2. The apparatus according to claim 1, wherein the Y-
A linear motor provided on one side of a base of a predetermined size;
An LM guide provided on the base and slidably supporting both sides of the lower surface of the X-axis base located on the upper side;
A friction pad provided on both sides in the inner direction of the LM guide formed on both sides; And
And a linear scale located at the center for detecting the movement amount of the X-axis base. The method according to claim 1,
Wherein the piezoelectric actuator receives a value of an interferometer for detecting a movement amount of the base plate, and feeds back the value to control driving of the nano-stage.

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