JP2001153984A - Measuring method for laser beam by x/y stage, and x/y stage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the degradation phenomenon of a laser beam on the basis of the interference of reflected light from the laser beam by two slits which are formed in a slit plate for origin return, in a slider part which is moved on a lattice platen part constituting an X/Y stage. SOLUTION: A slider irradiates the laser beam in the X-axis direction and the Y-axis direction, moves while performing positioning by the interference of the reflected light from the laser beam. It performs an origin return operation by making use of the slits in the slit plate for origin return. At least the two slits which are parallel and which have the same slit width are formed in the slit plate for origin return. The two slits measure the wavelength of the laser beam on the basis of the interference difference of the reflected light from the laser beam from an origin position positioned by the same detecting element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of measuring a laser beam of an X / Y stage and an X / Y stage, and more particularly to a method of measuring an X / Y direction on a grating platen based on interference of reflected light of the laser beam. The present invention relates to a method for automatically measuring the wavelength of a laser beam in a slider section that moves in the Y-axis direction.

[0002]

2. Description of the Related Art X for performing a home position return operation in the prior art.
As shown in FIG. 6, the / Y stage has a grid platen section 10 in which teeth 11 made of an iron plate, which is a magnetic material having a constant pitch, are formed in a grid shape, and the grid platen section 10 is moved in the X-axis direction and the Y-axis direction. Slider part 2 which can levitate and move
0, an X-axis mirror section 30 formed of a mirror provided at the X-axis side end and reflecting a laser beam, and a Y-axis mirror section 31 formed of a mirror provided at the Y-axis side end and reflecting a laser beam;
A servo driver (motor driving device) 40 for controlling the driving of the slider section 20 in the X-axis and Y-axis directions.

[0003] The slider section 20 is formed by a floating means (not shown), a core and a coil which are moved in the X-axis / Y-axis directions by magnetic attraction. Constitutes a linear motor. Above it, the X-axis mirror unit 30 (not shown) is irradiated with the laser beams 12 and 13, and X-rays are generated by interference of the reflected light.
X1-axis laser interferometer 21 and X for detecting axial position
It comprises a two-axis laser interferometer 22 and a Y-axis laser interferometer 23 which irradiates the Y-axis mirror section 31 with the laser beam 14 and detects the position in the Y-axis direction by interference of the reflected light. X1-axis laser interferometer 21 and X2-axis laser interferometer 22
Are arranged in parallel at a predetermined interval, and are configured to control yawing of the slider section 20.

In such a configuration, the slider section 20
Can move on the lattice platen unit 10 by magnetic attraction, and the servo driver (motor driving device) 40 connected to the slider unit 20 can control the X1-axis and X2-axis laser interferometers 21 and 22 on the slider unit 20. Y-axis laser interferometer 2
Positioning control is performed using the position signal of No. 3. That is, the X1-axis and X2-axis laser interferometers 21 and 22 fixed to the slider unit 20 control the X-axis direction position and the rotation angle θ of the slider unit 20, and the Y-axis laser interferometer 23 determines the Y-axis position. To detect. The origin of the slider section 20 is returned to the original position by positioning the slider section 20 such that the corner portion of the slider section 20 abuts on the intersection of the X-axis end and the Y-axis end.

However, in such a method of positioning the origin return at the corner between the X-axis end and the Y-axis end, positioning in the X-axis and Y-axis directions is performed by hitting the corner. In addition, the origin return operation can be easily performed in the θ rotation axis direction. On the other hand, dust is generated, and X1-axis and X2-axis laser interferometers 21, 22,
There is a limit to the adverse effect on the Y-axis laser interferometer 23 and the limit to accurate positioning.

[0006]

In an X / Y stage that moves while being positioned by interference of reflected light of a laser beam,
If the wavelength λ of the laser beam changes due to aging, a position detection error occurs. In addition, there is a problem that even if the position detection error increases, the user does not know until the user finds the problem.

Therefore, in order to maintain the positioning accuracy, it is necessary to periodically measure the wavelength of the laser beam and reset it to the servo driver. The measurement can be performed with a wavelength measuring instrument, but this is expensive for the slider part and is not held by ordinary users, so a large amount of time is required before recovery without knowing the cause of the failure. There is a problem of spending.

Therefore, there is a problem to be solved by a simple method for detecting a deterioration phenomenon of a laser beam due to aging in a slider portion which moves while being positioned by interference of reflected light of the laser beam.

[0009]

In order to solve the above-mentioned problems, an X / Y stage according to the present invention has the following configuration. (1) A slider that irradiates a laser beam in the X-axis direction and the Y-axis direction, moves while positioning by interference of the reflected light, and performs a home return operation using a slit of a home return slit plate. The slit plate for returning to the origin is provided with at least two slits having a parallel and the same slit width, and each of the two slits is a reflection light of a laser beam from an origin position positioned by the same detection element. A method of measuring a laser beam of an X / Y stage, comprising measuring a wavelength of a laser beam from an interference difference. (2) One of the two slits is a Y slit that determines the origin position of the slider in the Y-axis direction.
The method according to (1), wherein the other slit is a wavelength calibration C slit. (3) A lattice platen having teeth formed at a constant pitch along the X-axis direction and the Y-axis direction, and magnetically attracted while floating on the lattice platen and utilizing interference of reflected light of a laser beam. A slider portion capable of moving in the X-axis direction and the Y-axis direction by force, means for detecting an origin position by at least two slits provided in the slider portion and being parallel and having the same slit width; Means for measuring the wavelength of the laser beam from the interference difference of the reflected light of the laser beam at the origin position detected by the same detection element. (4) The X / Y stage according to (3), wherein the two slits are provided on a slit plate for returning to the origin used when the slider portion is returned to a predetermined position on the lattice platen. (5) The slits of the slit for returning to the origin include two X1 slits and X2 slits serially separated in the Y-axis direction, a Y slit provided in a direction orthogonal to the X1 slits and the X2 slit, and a Y slit. The X / Y stage according to (4), comprising a slit and a wavelength calibration C slit formed in parallel with the same slit width. (6) The positional relationship between the slits provided on the slit for returning to the origin is the position outside the X1 slit and the Y slit is provided in a direction orthogonal to the slit, and the position outside the X2 slit and orthogonal. X / Y according to (5), wherein a wavelength calibration C slit is provided in the direction.
stage. (7) The slider section is provided with a temperature sensor for detecting a temperature of the slit for returning to the origin, and correcting a signal detected by the two slits based on a signal detected by the temperature sensor. X described in (4), which is a feature
/ Y stage.

As described above, when the slider portion returns to the origin position, at least two origin positions are determined, and the wavelength of the laser beam is measured from the interference difference of the reflected light of the laser beam at that time. Each time the home position return operation is performed, the wavelength of the laser beam can be measured, and the positioning accuracy of the slider can be maintained with high accuracy.

[0011]

Next, an embodiment of an X / Y stage according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, the X / Y stage according to the present invention has a tooth 1 made of an iron plate which is a magnetic material having a constant pitch.
1 is formed in a grid shape, a slider portion 20 that can move on the grid platen portion 10 in the X-axis direction and the Y-axis direction, and laser beams 12 and 13 provided at the X-axis side end. -Axis mirror unit 3 composed of a mirror that reflects light
0, a Y-axis mirror section 31 provided at the Y-axis end and formed of a mirror for reflecting the laser beam 14, an origin sensor section 50 provided at a predetermined position on the X-axis end side, and the X-axis mirror section. And a servo driver (motor drive device) 40 that controls the drive in the Y-axis direction.

The slider section 20 includes a rotor composed of a floating means (not shown) which floats by a pneumatic bearing mechanism, a core and a coil which are moved in the X-axis / Y-axis directions by magnetic attraction, and a slit plate 60 for returning to origin. And a slit temperature sensor 70 for detecting the temperature. Above it, the X-axis mirror unit 30 is irradiated with laser beams 12 and 13 to detect the position in the X-axis direction by interference of the reflected light.
A one-axis laser interferometer 21 and an X2-axis laser interferometer 22,
A Y-axis laser interferometer 23 for irradiating the Y-axis mirror section 31 with the laser beam 14 and detecting a position in the Y-axis direction by interference of the reflected light, and a slit plate for origin return provided in the X-axis direction of the slider section 20 60. The X1-axis laser interferometer 21 and the X2-axis laser interferometer 22 are arranged at a predetermined interval to control the yawing of the slider unit 20.

The origin return slit plate 60 is formed of a glass slit, and includes an X1 slit 61 and an X2 slit 62, which are two slits separated in series on a straight line in the Y-axis direction, and a position outside the X1 slit 61. , And a C-slit 64 for wavelength calibration provided in a positional relationship orthogonal to the outer position of the X2 slit 62. The wavelength calibration C slit 64 is formed parallel to the Y slit 63 and has the same slit width. A means for detecting the origin position is formed by the Y slit 63 and the wavelength calibration C slit 64.

The origin sensor unit 50 is, as shown in FIG.
An irradiating light generator 58 for generating irradiating light composed of a laser beam 57, and two detecting elements 5 arranged at a predetermined interval.
An X-axis detection element 53 composed of 1 and 52, and two detection elements 5 arranged in a direction orthogonal to the X-axis detection element 53.
4 and 55, and a Y-axis detection element 56. The interval (width) between these two detection elements 51, 52 and 54, 55 is X1 slit 61 and X2 slit 6
2, formed about one third of the slit width of the Y slit 63 and the C slit 64.

In such a configuration, the slider section 20
Can move on the lattice platen unit 10 by magnetic attraction, and the servo driver 40 connected to the slider unit 20 can control the X1-axis and X2-axis laser interferometers 21 and 22 on the slider unit 20 and the Y-axis laser interferometer. Positioning control is performed using the 23 position signals. That is, the position in the X-axis direction obtained by the interference of the reflected light of the laser beams 12 and 13 from the X1-axis and X2-axis laser interferometers 21 and 22 fixed to the slider unit 20 and the rotation angle θ of the slider unit 20 are controlled. Then, the position in the Y-axis direction obtained by interference of the reflected light of the laser beam 14 from the Y-axis laser interferometer 23 is detected. An origin return slit plate 60 provided in the X-axis direction of the slider portion 20 is provided at an origin sensor portion 5 provided at the X-axis end of the lattice platen portion 10.
The zero point return operation of X / Y / θ is performed by adjusting to zero.

First, as shown in FIG. 3, when the Y slit 63 reaches the Y origin position where the Y-axis detecting element 56 of the origin sensor unit 50 is located, as shown in FIG. The signal is switched on / off. Thereby, the servo driver 40 moves the slider section 20 to the Y-axis position where the Y slit 63 coincides with the Y origin position.
Can be positioned. The Y detection position obtained by the interference of the reflected light of the laser beam 14 from the Y-axis laser interferometer 23 at this time is defined as Yo. Next, as shown in FIG. 4, the slider unit 20 is moved in parallel with the X-axis mirror unit 30 to position the C slit 64 so as to coincide with the Y origin position. The Y detection position obtained by the interference of the reflected light of the laser beam 14 from the Y-axis laser interferometer 23 at this time is defined as Yc. The laser wavelength λn of the laser beam at this time can be obtained by the following equation. λn = K · Lc / (Yc−Yo) (3) Here, K is a constant determined by design, and Lc is measured at the distance between the Y slit and the C slit at the time of manufacturing, and is set in the servo driver 40. Is what it is. The reflected light of the laser beam 14 at the origin position where each of the two slits (Y slit 63 and C slit 64) is detected by the same detection element (Y origin position (56) of the origin sensor unit 50) according to the equation (3). This is a means for measuring the wavelength of the laser beam 14 from the interference.

In this manner, the slider 2 is moved in the Y-axis direction.
By moving 0, the Y slit 63 and the C slit 6
4 is performed using the same origin sensor unit 50, and the distance relations Yo and Yc are calculated. Then, if the laser wavelength λn is calculated based on the above equation (3), the deterioration phenomenon of the laser beam can be measured every time the home position return operation is performed. This is because the X1 slit 61 and the X2 slit 62 already installed
Needless to say, the measurement may be performed by using a combination of the X1 and X2 slits 61 and 62, the Y slit 63, and the C slit 64. It is. In such a configuration, if the wavelength of the laser beam is measured,
The detection of the laser beam can be realized at low cost, and high positioning accuracy can be maintained even if the laser beam changes over time. In the case of a so-called laser interferometer failure accompanied by a large change in the wavelength of the laser beam, it is possible to detect the state at an early stage and issue a warning to the user. Further, in an environment in which the temperature and the atmospheric pressure change slowly, it is not necessary to perform the refractive index correction by automatically correcting the wavelength at appropriate time intervals. That is, the temperature and pressure sensors are not required, and the cost is reduced.

The home return slit plate 60 slightly expands and contracts depending on the temperature. The length of expansion and contraction can be corrected by the temperature detected by the slit temperature sensor, and can be taken into account.
For example, temperature error ΔT = ± 1 ° C., Lc = 150 mm,
Set the linear expansion coefficient of the home return slit plate 60 to 0.5 × 10 ^-6.
Then, the error included in Lc is 0.15 (m) × 0.5 × 10 ⁻⁶ × 1 = 0.075 × 1
0 ^-6.

If the reproduction accuracy of the origin signal of the origin sensor unit 50 is ± 0.1 μm, the temperature error occurring at (Yc−Yo) is ± 0.2 μm. Therefore, the laser wavelength λn
Is approximately (0.075 × 10−6 + 0.2 × 10−6) /0.1
5 = 1.2 × 10−6 = 1.8 ppm, and the position detection error that occurs when the distance between the X-axis mirror unit 30 and the X1-axis and X2-axis laser interferometers 21 and 22 is 1 m falls within about 2 μm.

As described above, in the embodiment, the positional relationship between the C slit 64 and the Y slit 63 is the same, and
If the distance between the slit 63 is made as long as possible, measuring the error between the detection accuracy of the Y slit 63 and the detection accuracy of the C slit 64 for wavelength calibration allows early detection of the deterioration phenomenon of the laser beam of the laser interferometer. It is possible to do.

[0022]

As described above, according to the present invention, X /
The Y stage measures the laser beam wavelength based on the interference difference of the reflected light of the laser beam from different positions of the slider part using two slits when returning to the origin, so that the laser beam changes over time. However, even if the occurrence of the slider occurs, the deterioration phenomenon can be detected at an early stage, and there is an effect that a high positioning accuracy of the slider can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing the movement of a slider moving on a grating platen provided with an origin return means in an X / Y stage according to the present invention.

FIG. 2 is a diagram illustrating a configuration example of an origin sensor unit.

FIG. 3 is a plan view schematically showing the origin position return of a Y slit by the origin return means.

FIG. 4 is a plan view schematically showing an origin position return of the wavelength calibration C slit of the origin return means.

FIG. 5 is a waveform diagram showing an error between a Y slit of the origin return means and a C slit for wavelength calibration by a signal.

FIG. 6 is an explanatory diagram showing a state in which a slider portion is applied to a corner portion between an X axis and a Y axis in the related art to perform an origin return operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lattice platen part 11 Teeth 12 Laser beam 13 Laser beam 14 Laser beam 20 Slider 21 X1 axis laser interferometer 22 X2 axis laser interferometer 23 Y axis laser interferometer 30 X axis mirror section 31 Y axis mirror section 40 Servo driver 50 Origin sensor unit 51 Detector 52 Detector 53 X-axis detector 54 Detector 55 Detector 56 Y-axis detector 57 Laser beam 58 Irradiation light generator 60 Origin return slit plate 61 X1 slit 62 X2 slit 63 Y slit 64 C slit 70 Temperature sensor for slit

Claims (7)

[Claims] A laser beam is irradiated in the X-axis direction and the Y-axis direction, the laser beam is moved while positioning by interference of the reflected light, and an origin return operation is performed using a slit of a slit plate for origin return. A slider, wherein the slit for returning to the origin is provided with at least two slits having the same slit width in parallel, and each of the two slits reflects a laser beam from the origin position positioned by the same detection element. A method for measuring a laser beam of an X / Y stage, comprising measuring a wavelength of a laser beam from an interference difference of light. 2. The X-axis detector according to claim 1, wherein one of the two slits is a Y-slit for determining an origin position of the slider in the Y-axis direction, and the other slit is a wavelength-calibrating C-slit. / Y-stage laser beam measurement method. 3. A grid platen having teeth formed at a constant pitch along the X-axis direction and the Y-axis direction, and is floated on the grid platen and positioned while utilizing interference of reflected light of a laser beam. A slider portion movable in the X-axis direction and the Y-axis direction by magnetic attraction, means for detecting an origin position by at least two slits provided in the slider portion in parallel and having the same slit width; Means for measuring the wavelength of the laser beam from the interference difference of the reflected light of the laser beam at the origin position where each of the slits is detected by the same detection element. 4. The home position return slit plate used for returning the slider portion to a predetermined position on the lattice platen, wherein the two slits are provided.
X / Y stage described in 1. 5. The slit of the slit plate for returning to the origin,
Two X1 slits and X2 separated in series in the Y-axis direction
5. The slit according to claim 4, comprising a slit, a Y slit provided in a direction orthogonal to the X1 slit and the X2 slit, and a wavelength calibration C slit formed in parallel with the Y slit and having the same slit width. X / Y stage. 6. A positional relationship between the slits provided in the slit plate for returning to the origin is a position outside the X1 slit and the Y slit is provided in a direction orthogonal to the X1 slit, and a position outside the X2 slit. The X / Y stage according to claim 5, wherein a C slit for wavelength calibration is provided in a direction orthogonal to the X / Y stage. 7. The slider unit is provided with a temperature sensor for detecting a temperature of the origin return slit plate, and corrects a signal detected by the two slits based on a signal detected by the temperature sensor. The X / Y stage according to claim 4, wherein: