JP4716178B2 - XY stage - Google Patents

Description

  The present invention has a laser interferometer and a bar mirror that reflects the irradiation beam of the laser interferometer. The laser interferometer and the bar mirror move relative to each other according to the movement of the slider, and the position is detected by the laser interferometer. The present invention relates to an XY stage that controls the position of a slider portion in a two-dimensional direction on a platen.

  An XY stage that detects the position of a slider part whose position is controlled in a two-dimensional direction on a platen by using a fixedly arranged laser interferometer and a bar mirror mounted on a slider part that reflects an irradiation beam of the laser interferometer is Patent Document 1 discloses this.

  FIG. 6 is a plan view showing an image of an initial position in a conventional XY stage. Reference numeral 1 denotes a quadrilateral slider portion whose position is controlled in a two-dimensional direction on a platen (not shown), and includes bar mirrors 11 and 12 in the Y axis direction and the X axis direction of two adjacent sides. It is assumed that the slider unit 1 is rotated by a predetermined angle in the clockwise direction with respect to the reference XY axis at the initial position.

  21, 22 and 23 are fixedly arranged laser interferometers. The laser interferometer 21 irradiates the bar mirror 11 in the Y-axis direction with the laser beam Bx in the X-axis direction, inputs the reflected beam, and determines the position (distance from the reference point) of the slider unit 1 in the X-axis direction. taking measurement.

  The laser interferometers 22 and 23 irradiate a pair of laser beams By 1 and By 2 in the Y-axis direction at a predetermined distance from the bar mirror 12 in the X-axis direction, and input the reflected beams to input the Y-axis of the slider unit 1. The direction position (distance from the reference point) and the Z-axis rotation angle are measured. The details of the measurement principle of the rotation angle are disclosed in Patent Document 2.

  When starting the position control of the slider unit 1 by the laser interferometer, it is necessary to correct the rotation by moving the slider unit 1 to the origin position of the platen in the stepping motor mode. For this reason, rotation angle information at the initial position is required.

  FIG. 7 is a functional block diagram for explaining the measurement principle of the laser interferometer that measures the distance by reflection from the bar mirror. Reference numeral 100 denotes a bar mirror provided on the moving slider, and reference numeral 200 denotes a laser interferometer fixedly arranged. The relationship between the bar mirror 100 and the laser interferometer 200 is relative, and the moving and fixed arrangement relationship may be reversed.

  In the laser interferometer 200, a half mirror 202, mirrors 203 and 204, a deflection beam splitter (hereinafter referred to as PBS) 205, a λ / 4 plate 206, and a corner cube 207 are located at predetermined positions in the optical path of the outgoing beam from the laser light source 201. Is arranged.

  The beam emitted from the laser light source 201 travels along the path of the half mirror 202, the mirror 203, the mirror 204, and the half mirror 202, and there is light traveling in the direction a in the figure. This light is the first light.

  The beam emitted from the laser light source 201 includes a half mirror 202, a PBS 205, a λ / 4 plate 206, a first path B1 (irradiation), a bar mirror 100, a first path B1 (reflection), a λ / 4 plate 206, a PBS 205. , Corner cube 207, λ / 4 plate 206, second path B2 (irradiation), bar mirror 100, second path B2 (reflection), λ / 4 plate 206, PBS 205, half mirror 202, and a ′ in FIG. There is light traveling in the direction. This light is the second light.

  The mirror 203 is disposed at an angle of 45 ° with the optical axis of the laser light source 201. In contrast, the mirror 204 is disposed at an angle of (45 ° + θa) with the optical axis of the laser light source 201. Since the arrangement angle of the mirror 204 is shifted by θa, the wavefront of the first light a is shifted by θa with respect to the wavefront of the second light a ′. Thereby, the first light and the second light interfere to form an interference fringe S. A photodiode array (hereinafter referred to as PDA) 208 detects the interference fringes S.

  The PDA 208 is composed of four photodiodes 208A to 208D. The four photodiodes 208A to 208D are arranged within one pitch of the interference fringes S, and each photodiode is arranged by being shifted by p / 4 (p is the pitch of the interference fringes). The pitch p of the interference fringes is p = λ / θa (λ is the wavelength of the laser beam).

  The subtractor 209 performs an operation of (detection signal of the photodiode 208A) − (detection signal of the photodiode 208C). The subtractor 210 performs an operation of (detection signal of the photodiode 208B) − (detection signal of the photodiode 208D).

  When the bar mirror 100 moves with the movement of the slider portion, the interference fringes S move in the direction of the arrow dd ′. When the interference fringes move, the bright and dark portions of the interference fringes that hit the photodiodes 208A to 208D move, and the detection values of the photodiodes 208A to 208D change. Based on this, the position of the bar mirror 100 is calculated. Details of the position calculation method are disclosed in Patent Document 1.

JP 2005-9952 A

JP 2000-65970 A

  As is apparent from the measurement principle of FIG. 7, the first and second paths B1 and B2 of the laser beam reciprocating between the bar mirror 100 and the laser interferometer 200 have an irradiation optical axis and a reflection optical axis within a predetermined error range. If the irradiation optical axis and the reflection optical axis are deviated beyond this, interference fringes cannot be generated, and distance measurement becomes impossible.

  When the rotation at the slider initial position shown in FIG. 6 deviates beyond the allowable range of deviation of the reciprocating optical axis of the first path B1 and the second path B2, the distance by the laser interferometers 22 and 23 The Z-axis rotation angle cannot be calculated based on the difference between the measured values, and the rotation angle information for correcting the rotation by moving to the origin position cannot be calculated by the laser interferometer itself.

  For this reason, in the prior art, the angle sensor 40 is disposed between the fixing member 30 fixed in the X-axis (or Y-axis) direction and one side of the slider unit 1 to measure the initial position rotation angle of the slider unit 1. Then, the rotation correction was executed in a state in which it moved to the origin position based on the angle measurement information.

  The prior art requires an angle sensor for measuring the initial position rotation angle, and occupies the space around the stage. Further, since setting and reading of the sensor are executed manually, there is a problem that the operation is complicated.

  The present invention has been made to solve the above-described problems, and the laser interferometer itself has a function of detecting the initial position rotation, so that the rotation direction and rotation angle of the slider portion can be automatically detected. The purpose is to realize an XY stage.

In order to achieve such a subject, the present invention has the following configuration.
(1) A laser interferometer and a bar mirror that reflects an irradiation beam of the laser interferometer are provided, and the laser interferometer and the bar mirror move relative to each other according to the movement of the slider portion. In the XY stage for controlling the position of the detected slider part in a two-dimensional direction on the platen,
A rotation detecting means for detecting the reflected beam of the bar mirror and detecting the rotation of the slider portion from the detected reflected beam ;
The rotation detecting means includes
A pair of reflecting members provided at symmetrical positions across the optical axis of the irradiation beam irradiated from the laser interferometer and passing through the rotation detecting means and irradiated on the bar mirror;
A pair of optical sensor means for receiving the reflected beam from the reflecting member;
An XY stage characterized by comprising:

( 2 ) The XY stage according to ( 1 ), wherein the rotation detection unit detects at least one of a rotation direction and a rotation angle of the slider portion based on a differential output value of the pair of optical sensor units.

( 3 ) The XY stage according to ( 2 ), further comprising initial control means for rotating the slider unit so that the differential output value becomes zero.

( 4 ) The XY stage according to ( 2 ) or ( 3 ), wherein the difference output value has a predetermined dead zone in detection of a rotation angle.

( 5 ) The optical sensor means is composed of photodiode means for generating an output corresponding to a light receiving angle of a reflected beam from the bar mirror. ( 1 ) to ( 4 ), XY stage.

As is apparent from the above description, the present invention has the following effects.
An angle sensor that detects the initial position rotation is not required, and the laser interferometer itself can automatically detect the rotation direction and angle of the initial position of the slider. And troublesome troublesome operations for reading.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram of a main part showing an embodiment of an XY stage provided with a rotation detecting means to which the present invention is applied. The same elements as those of the conventional stage described with reference to FIGS. Hereinafter, the characteristic part of the present invention will be described.

  1A is a plan view of the main part, and FIG. 1B is a side view thereof. A dotted line block 500 is a rotation detecting means forming a characteristic part of the present invention. This rotation detecting means is detachably unitized, and is inserted when the reflected beam from the bar mirror 100 does not return to the laser interferometer 200 when measuring the initial position rotation of the slider portion, and when the rotation angle measurement is completed. Removed.

  In the rotation detecting unit 500, reference numeral 501 denotes a light shielding / aperture plate that shields the beam of the second path B2 from the laser interferometer 200 to the bar mirror 100 and from the aperture hole 501a formed through the first path B1. The beam is focused to irradiate the bar mirror 100.

  Reference numerals 502 and 503 denote a pair of reflecting members, which are symmetrically arranged at a predetermined distance s across the normal optical axis of the first path B1 on the bar mirror 100 side of the light shielding / aperture plate 501. As shown in the side view of FIG. 1B, the shape of the reflecting member is such that when a reflected beam B1 ′ (a beam deviated from the normal optical axis) is received from the bar mirror 100, the beam is indicated by B1 ″. Reflect 90 degrees downward.

  Reference numerals 504 and 505 denote a pair of optical sensor means. These optical sensor means are disposed below the reflecting members 502 and 503 so as to receive the reflected beam B1 ″ from the reflecting members 502 and 503.

  These optical sensor means 504 and 505 have a clockwise or counterclockwise shift angle of the reflected beam B1 ′ (a beam shifted from the normal optical axis) from the bar mirror 100 around the normal optical axis of the first path B1. This is realized by a PSD (Position Sensing Device) using photodiode means that outputs an angle detection current in a differential manner.

  FIG. 2 is an image diagram showing a state where the slider portion is rotating and the reflected beam of the first path B1 from the bar mirror is shifted from the normal optical axis and is incident on the reflecting member 503 of the rotation detecting means as B1 ′. The beam B1 ″ reflected by the reflecting member 503 is incident on the optical sensor means 504 and 505 and converted into a differential angle detection current.

  FIG. 3 is a functional block diagram showing the signal processing configuration of the differential angle detection current of the optical sensor means. The output current I1 of the optical sensor means 504 is converted into a voltage signal V1 by the I / V converter 506. Similarly, the output current I2 of the optical sensor means 505 is converted into a voltage signal V2 by the I / V converter 507.

  These voltage signals V1 and V2 are difference-calculated by the difference calculation means 508, and a difference output value θz is calculated. The difference output value θz is rotation information of the initial position of the slider unit. Reference numeral 509 denotes an initial control unit that inputs a differential output value θz and executes rotation angle correction control of the slider unit that has been moved to the origin position so that θz becomes zero.

  FIG. 4 is a characteristic diagram showing the relationship of the differential output value θz with respect to the rotation angle θ of the slider portion. In this characteristic diagram, the dead zone in the vicinity of zero of the rotation angle θ is determined to an arbitrary width by the gap s between the reflecting members 502 and 503 shown in FIG. The deviation of the dead band width range is set as an allowable range, and the rotation angle correction control is not executed.

  FIG. 5 is an image diagram in which the present invention is applied to a multi-slider system. In a multi-slider system that controls the position of a plurality of slider parts having bar mirrors on three sides on the platen, the bar mirror of the slider part A is positioned in front of the laser interferometer 200 as shown in FIG. As shown in FIG. 5B, the bar mirror of the slider part A may not be positioned in front of the laser interferometer 200.

  If the rotation detecting means 500 of the present invention is used, if the slider portion is rotating at the time of initialization, the rotation can be detected in the relationship of FIG. 5A, but the rotation cannot be detected in the relationship of FIG. By utilizing this, the slider part where the laser interferometer and the bar mirror are opposed can be confirmed, and control of the multi-slider system can be supported.

It is a functional block diagram of the principal part which shows one Embodiment of XY stage provided with the rotation detection means to which this invention is applied. It is an image figure which shows the state which the slider part rotated and the reflected beam from a bar mirror shifted | deviated from the normal optical axis. It is a functional block diagram which shows the signal processing structure of the differential angle detection current of an optical sensor means. It is a characteristic view which shows the relationship of the difference output value with respect to the rotation angle of a slider part. It is an image figure which applied this invention to the multi-slider system. It is a top view which shows the image of the initial position in the conventional XY stage. It is a functional block diagram explaining the measurement principle of the laser interferometer which measures distance by reflection from a bar mirror.

Explanation of symbols

100 bar mirror 200 laser interferometer 205 deflection beam splitter (PBS)
206 λ / 4 plate 207 Corner cube 500 Rotation detection means 501 Shading / aperture plate 501a Aperture hole 502, 503 Reflective member 504, 505 Optical sensor means (PSD)

Claims (5)

A laser interferometer and a bar mirror that reflects the irradiation beam of the laser interferometer are provided. The laser interferometer and the bar mirror move relative to each other according to the movement of the slider portion, and the position is detected by the laser interferometer. In an XY stage for controlling the position of the slider part in a two-dimensional direction on the platen,
A rotation detecting means for detecting the reflected beam of the bar mirror and detecting the rotation of the slider portion from the detected reflected beam ;
The rotation detecting means includes
A pair of reflecting members provided at symmetrical positions across the optical axis of the irradiation beam irradiated from the laser interferometer and passing through the rotation detecting means and irradiated on the bar mirror;
A pair of optical sensor means for receiving the reflected beam from the reflecting member;
An XY stage characterized by comprising: 2. The XY stage according to claim 1 , wherein the rotation detection unit detects at least one of a rotation direction and a rotation angle of the slider unit based on a differential output value of the pair of optical sensor units. The XY stage according to claim 2 , further comprising initial control means for rotating the slider unit so that the differential output value becomes zero. The difference output values, XY stage according to claim 2 or 3, characterized in that it has a predetermined dead zone in the detection of the rotation angle. It said optical sensor means, XY stage according to any one of claims 1 to 4, characterized in that it is constituted by a photodiode means for generating an output corresponding to the light-receiving angle of the reflected beam from the bar mirror.

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