JP2005025695A - Xy stage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an XY stage provided with a function of suppressing pitching and rolling when vibration occurs during accelerating, decelerating, and constant speed movement of a slider part. <P>SOLUTION: The XY stage carrying out two-dimensional position control of the slider part is characterized by that it has a first Z-axis sensor outputting a signal for detecting a pitching angular velocity of the slider part, and a second Z-axis sensor outputting a signal for detecting a rolling angular velocity of the slider part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an XY stage that is used in a prober, a handler, a stepper, and the like and that performs two-dimensional positioning of an object.

  Patent Documents 1 and 2 disclose in detail the structure of an XY stage having a grating platen and a slider part whose position is controlled by sliding the upper surface of the grating platen in the X-axis direction and the Y-axis direction, and suppression of yawing of the slider part. ing.

JP 2000-65970 A JP 2001-125648 A

  FIG. 4 is a perspective view showing a basic structure of an XY stage having a conventional structure disclosed in Patent Document 1. As shown in FIG. Reference numeral 10 denotes a lattice platen fixedly arranged horizontally, and teeth are formed at a constant pitch along the X direction and the Y direction. In the figure, only a part of the teeth is shown for simplicity. The lattice platen is formed by cutting grooves in a lattice shape on the flat surface of the magnetic material.

  Reference numeral 20 denotes a slider portion that is positioned and controlled by sliding the upper surface of the grating platen in the X direction and the Y direction, and a workpiece and a target (not shown) to be positioned are mounted on the upper portion. The levitation means 21 is provided with a nozzle on the back surface facing the grid platen 10 and causes the lidar 20 to float on the grid platen 10 by injecting compressed air.

  Reference numerals 31 and 32 denote a first X-axis sensor and a second X-axis sensor that are fixedly arranged on the upper portion of the slider unit 20 with a predetermined distance in the X direction. Similarly, 33 is a Y-axis sensor fixedly disposed on the upper portion of the slider portion 20.

  Reference numeral 11 denotes an X-axis mirror having a predetermined height, which is fixedly disposed at one end of the X-axis of the grating platen 10 so as to be orthogonal to the X-axis, and includes a first X-axis sensor 31 and a second X-axis sensor 32. opposite. Reference numeral 12 denotes a Y-axis mirror having a predetermined height fixedly disposed at one end of the Y-axis of the grating platen 10 so as to be orthogonal to the Y-axis, and faces the Y-axis sensor 33.

  The first X-axis sensor 31, the second X-axis sensor 32, and the Y-axis sensor 33 are optical distance measuring devices, and irradiate the X-axis mirror 11 and the Y-axis mirror 12 with a laser beam and receive reflected light. The position of the slider unit 20 in the X direction and the Y direction is measured by measuring the moving distance using interference. PX1 and PX2 are X-axis direction distance measurement values by the first X-axis sensor 31 and the second X-axis sensor 32, and PY is a Y-direction distance measurement value by the Y-axis sensor 33.

  Reference numeral 41 denotes a first X-axis control unit, which transmits a current operation signal MX1 to a first X-axis motor formed on the slider unit 20 based on a deviation between the measured value PX1 and the position command signal SX1. Reference numeral 42 denotes a second X-axis control unit which transmits a current operation signal MX2 to a second X-axis motor formed on the slider unit 20 based on a deviation between the measured value PX2 and the position command signal SX2. Reference numeral 43 denotes a Y-axis control unit which transmits a current operation signal MY to a Y-axis motor formed on the slider unit 20 based on a deviation between the measured value PY and the position command signal SY.

  The structure of the first X-axis motor, the second X-axis motor, and the Y-axis motor, the configuration of the position control servo system, the method of suppressing yawing, etc. are disclosed in detail in Patent Documents 1 and 2, and will be described. Omitted.

  FIG. 5 is an image view of pitching and rolling of the slider unit 20 that floats and moves on the lattice platen 10. A swing P in the X direction indicated by a dotted arrow is pitching, and a swing in the Y direction indicated by an alternate long and short dashed line arrow is rolling.

  When the target mounted on the slider portion requires extremely high positioning accuracy, it is necessary to suppress pitching and rolling of the slider portion that floats and moves. In the techniques described in Patent Documents 1 and 2, yawing, which is the rotation of the slider portion in the Z-axis direction, can be suppressed, but pitching and rolling cannot be handled.

  An object of the present invention is to realize an XY stage having a function of suppressing pitching and rolling when vibration is generated during acceleration, deceleration, and constant speed movement of a slider portion.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
In the XY stage that controls the position of the slider part in a two-dimensional direction,
A first Z-axis sensor that outputs a signal for detecting a pitching angular velocity of the slider portion;
A second Z-axis sensor that outputs a signal for detecting a rolling angular velocity of the slider portion;
An XY stage characterized by comprising:

The invention according to claim 2
The first Z-axis sensor includes an accelerometer attached to both ends of the slider portion in the X-axis direction, and the second Z-axis sensor is attached to both ends of the slider portion in the Y-axis direction. The XY stage according to claim 1, wherein the XY stage is configured by an accelerometer.

The invention described in claim 3
Integrating the measured value of the first Z-axis sensor to detect the pitching angular velocity of the slider portion, and integrating the calculated value of the second Z-axis sensor to detect the rolling angular velocity of the slider portion. The XY stage according to claim 1, wherein the XY stage is characterized in that

The invention according to claim 4
The first Z-axis coil is provided close to the first Z-axis sensor, and the second Z-axis coil is provided close to the second Z-axis sensor. The XY stage according to any one of the above.

The invention according to claim 5
Pitching control means for exciting the first Z-axis coil based on the pitching angular velocity measurement value measured by the first Z-axis sensor, and the rolling angular velocity measurement value measured by the second Z-axis sensor. 5. The XY stage according to claim 1, further comprising a rolling control unit that excites two Z-axis coils.

The invention described in claim 6
Exciting the first Z-axis coil and the second Z-axis coil based on the measured value of the first Z-axis sensor and the Z-direction velocity of the slider portion measured by the second Z-axis sensor; 6. The XY stage according to claim 1, further comprising speed control means for controlling a Z-direction speed of the slider portion.

The invention described in claim 7
Pitching control means for exciting the first Z-axis coil based on the measured pitching angular velocity measured by the first Z-axis sensor;
Rolling control means for exciting the second Z-axis coil based on a rolling angular velocity measurement value measured by the second Z-axis sensor;
Speed control for exciting the first Z-axis coil and the second Z-axis coil based on the measured values of the first Z-axis sensor and the second Z-axis sensor to control the Z-direction speed of the slider portion. Means,
The XY stage according to claim 1, wherein the XY stage is provided.

The invention described in claim 8
The slider portion moves on the lattice platen, and the length of the core facing the lattice platen in the first and second Z-axis coils is selected to be an integral multiple of the lattice pitch of the lattice platen. The XY stage according to claim 1, wherein the XY stage is characterized in that

The invention according to claim 9
The XY stage according to any one of claims 1 to 8, wherein the first and second Z-axis sensors are servo accelerometers.

The invention according to claim 10 is:
The XY stage according to any one of claims 1 to 8, wherein the first and second Z-axis sensors measure an electromotive force generated in a coil.

The invention according to claim 11
The XY stage according to any one of claims 1 to 8, wherein the first and second Z-axis sensors measure an electromotive force generated in the piezoelectric element.

As is apparent from the above description, the present invention has the following effects.
(1) An XY stage having a function of suppressing pitching and rolling during acceleration, deceleration, and constant speed movement of the slider portion can be realized.
(2) By controlling the Z-direction speed of the slider portion in addition to the control of the pitching angular velocity and the rolling angular velocity, an XY stage with further improved pitching and rolling suppression accuracy can be realized.
(3) By making the pitching control means, rolling control means, and speed control means independent, pitching and rolling suppression without mutual interference is possible.
(4) By selecting the length of the core facing the grid platen in the Z-axis coil as an integer multiple of the grid pitch, highly accurate servo control can be realized.
(5) As the Z-axis sensor, a commercially available small, inexpensive, and high-accuracy accelerometer such as a servo accelerometer can be easily adopted, which can contribute to the cost reduction of the apparatus.

Hereinafter, the present invention will be described in detail with reference to the drawings.
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view and a side view showing an example of an XY stage to which the present invention is applied. The same elements as those described in the conventional example of FIG.

  1A is a plan view of the grating platen 10 and the slider portion 20, and FIG. 1B is a side view in the X-axis direction (Y-axis direction sensor not shown). The slider portion 20 is levitated with a small gap on the upper surface of the lattice platen 10 by jetting compressed air. Since the levitation means does not have a function of controlling the gap to be constant, the pitching and rolling described with reference to FIG.

  The Z1 sensor 101 and the Z2 sensor 102 are accelerometers attached to both ends of the slider unit 20 in the X-axis direction, and form a first Z-axis sensor. Pitching angular velocity is measured by integrating the measured values of these accelerometers. In this case, the slider unit 20 moves in the X-axis direction.

  Similarly, the Z3 sensor 103 and the Z4 sensor 104 are accelerometers attached to both ends of the slider unit 20 in the Y-axis direction, and form a second Z-axis sensor. The rolling angular velocity is measured by integrating the measured values of these accelerometers. In this case, the slider unit 20 moves in the X-axis direction.

  When the slider unit 20 is moving in the Y-axis direction, the Z3 sensor 103 and the Z4 sensor 104 detect the pitching angle, and the Z1 sensor 101 and the Z2 sensor 102 detect the rolling angle.

  As shown in FIG. 1B, the Z1 sensor 101 and the Z2 sensor 102 measure accelerations a1 and a2 in the lattice platen direction (Z direction) of the slider unit 20 at the sensor position. Although not shown, the Z3 sensor 103 and the Z4 sensor 104 similarly measure accelerations a3 and a4 in the direction of the lattice platen 10 (Z direction) of the slider unit 20 at the sensor position.

  The distance between the Z1 sensor 101 and the Z2 sensor 102 and the distance between the Z3 sensor 103 and the Z4 sensor 104 are the same distance L here, but may be different. The pitching angular velocity is detected by the acceleration measurement values a1 and a2 of the Z1 sensor 101 and the Z2 sensor 102, the X-direction distance L of the slider portion, and the integration calculator. Similarly, the measured values a3 and a4 of the Z3 sensor 103 and the Z4 sensor 104, the Y-direction distance L of the slider unit, and the rolling angular velocity of the slider unit in the Y direction are detected.

The pitching angular velocity pz and the rolling angular velocity rz are approximately calculated by the following equations.
pz = (a1-a2) / L · (1 / S) (1)
rz = (a3-a4) / L · (1 / S) (2)
S: Laplace operator

Furthermore, the slider unit 20Z-direction speed hz is calculated by the following equation using the measured values of the four accelerometers and the integral calculator.
hz = (a1 + a2 + a3 + a4) / 4 · 1 / S (3)

  The Z1 coil 105 and the Z2 coil 106 are provided close to the Z1 sensor 101 and the Z2 sensor 102, and form a first Z-axis coil. Similarly, the Z3 coil 107 and the Z4 coil 108 are provided close to the Z3 sensor 103 and the Z4 sensor 104, and form a second Z-axis coil. By applying an exciting current to these coils, as shown in FIG. 1B, an attractive force is generated between the slider portion 20 and the lattice platen 10, and the distance of the gap can be individually controlled.

  FIG. 2 is a functional block diagram illustrating a configuration example of the pitching control unit, the rolling control unit, and the Z-direction speed control unit. Reference numerals 109 to 112 denote current amplifiers which supply excitation currents i1 to i4 for servo control to the Z1 coil 105 to Z4 coil 108, respectively.

  The difference between the measured value a1 of the Z1 sensor 101 and the measured value a2 of the Z2 sensor 102 is calculated by the subtractor 113, and the pitching angular velocity pz of the above equation (1) is calculated by the 1 / L calculation unit 114 and the integration calculation unit 132. The The difference between the measured value a3 of the Z3 sensor 103 and the measured value a4 of the Z4 sensor 104 is calculated by the subtractor 115, and the rolling angular velocity rz of the equation (2) is calculated by the 1 / L calculating unit 116 and the integral calculating unit 133. The The side constant values a1 to a4 of the Z1 sensor to the Z4 sensor are added by the adder 117, and the Z direction speed hz of the above equation (3) is calculated by the 1/4 calculation unit 118 and the integration calculation unit 134.

The subtractor 119 gives the difference between the measured value pz of the pitching angular velocity and the set value ps (0) of the pitching angular velocity command unit 120 to the error amplifier 121. The subtractor 122 uses the measured value rsz of the rolling angular velocity and the set value rs (0) of the rolling angular velocity command unit 123.
) Is applied to the error amplifier 124. The subtractor 125 gives the difference between the measured value hz of the Z direction speed and the set value hs of the speed command unit 126 to the error amplifier 127.

  The output vp of the error amplifier 121 that controls the pitching angular velocity is supplied to the current amplifiers 109 and 110 via the adder 128 and the subtractor 129, and reversibly manipulates the excitation currents i1 and i2 of the Z1 coils 105 and 106, The pitching angular velocity pz is controlled to be zero.

  Similarly, the output vr of the error amplifier 124 for controlling the rolling angular velocity is given to the current amplifiers 111 and 112 via the adder 130 and the subtractor 131, and the exciting currents i3 and i4 of the Z3 coils 107 and 108 are reversibly changed. Operate and control the rolling angular velocity rz to be zero.

  The output vh of the error amplifier 127 that controls the Z-direction speed of the slider unit is supplied to the current amplifiers 109 to 112 via the adders 128 and 130 and the subtractors 129 and 131, and the excitation currents i to Z1 to Z4 are supplied to the current amplifiers 109 to 112. i4 is operated to control the Z-direction speed hz between the slider portion 20 and the grating platen 10 to be zero.

  Thus, in addition to the pitching control means and the rolling control means, the speed control means for making the speed in the Z-axis direction of the slider portion constant is provided, so that the pitching at the time of acceleration, deceleration and constant speed movement of the slider portion is provided. In addition, the rolling suppression accuracy can be improved.

  Furthermore, in the present invention, the pitching control means, the rolling control means, and the Z-direction speed control means constitute an independent servo system, and each control system avoids mutual interference that affects the physical quantities of other control systems. Can do.

  FIG. 3 is a conceptual diagram showing the relationship between the lengths of the cores constituting the Z1 to Z4 coils and the lattice pitch of the lattice platen 10, and will be described by using the Z1 coil as a representative example. 105 is a winding of the Z1 coil, 105a is a core, (A) is a front view (B) is a side view. The hatched portion of the lattice platen 10 represents a nonmagnetic material.

  In FIG. 3A, the core width W on the front side is designed to be an integral multiple of the lattice pitch P, that is, W = nP. In FIG. 3B, the core widths D1 and D2 on the side surfaces are designed to be an integral multiple of the grating pitch P, that is, D1 = D2 = mP (m is an integer). Further, the distance G between the salient poles of the core is set so as to cancel each other when a lateral force (cogging) or pitching occurs due to variations in the magnetic flux distribution in the salient poles.

  By such setting of the core and the lattice pitch, the facing area between the core and the lattice is always constant, and the suction force generated by each coil is made uniform regardless of the position of the slider portion 20 on the lattice platen 10. And the servo control accuracy can be improved.

  The first and second Z-axis sensors are accelerometers. Specifically, servo accelerometers having gyro means are commercially available that are small, inexpensive, and highly accurate, and can be easily employed. In addition, an accelerometer based on the principle of detecting an electromotive force due to movement of a coil in a magnetic field and an accelerometer for detecting an electromotive force due to pressing on a piezoelectric element are commercially available and can be easily adopted.

It is the top view and side view of an XY stage to which the present invention is applied. It is a functional block diagram which shows the servo means of this invention. It is the front view and side view explaining the relationship between the length of the core which opposes the lattice platen in a Z-axis coil, and a lattice pitch. It is a perspective view explaining the structure of the conventional XY stage. It is a perspective view explaining the image of pitching and rolling which generate | occur | produce in a slider part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lattice platen 20 Slider part 101 Z1 sensor 102 Z2 sensor 103 Z3 sensor 104 Z4 sensor 105 Z1 coil 106 Z2 coil 107 Z3 coil 108 Z4 coil

Claims (11)

In the XY stage that controls the position of the slider part in a two-dimensional direction,
A first Z-axis sensor that outputs a signal for detecting a pitching angular velocity of the slider portion;
A second Z-axis sensor that outputs a signal for detecting a rolling angular velocity of the slider portion;
XY stage characterized by having.   The first Z-axis sensor includes an accelerometer attached to both ends of the slider portion in the X-axis direction, and the second Z-axis sensor is attached to both ends of the slider portion in the Y-axis direction. The XY stage according to claim 1, comprising an accelerometer.   Integrating the measured value of the first Z-axis sensor to detect the pitching angular velocity of the slider portion, and integrating the calculated value of the second Z-axis sensor to detect the rolling angular velocity of the slider portion. The XY stage according to claim 1 or 2, characterized in that   The first Z-axis coil is provided close to the first Z-axis sensor, and the second Z-axis coil is provided close to the second Z-axis sensor. XY stage in any one of.   Pitching control means for exciting the first Z-axis coil based on the pitching angular velocity measurement value measured by the first Z-axis sensor, and the rolling angular velocity measurement value measured by the second Z-axis sensor. The XY stage according to claim 1, further comprising a rolling control unit that excites two Z-axis coils.   Exciting the first Z-axis coil and the second Z-axis coil based on the measured value of the first Z-axis sensor and the Z-direction velocity of the slider portion measured by the second Z-axis sensor; 6. The XY stage according to claim 1, further comprising speed control means for controlling a Z-direction speed of the slider portion. Pitching control means for exciting the first Z-axis coil based on the measured pitching angular velocity measured by the first Z-axis sensor;
Rolling control means for exciting the second Z-axis coil based on a rolling angular velocity measurement value measured by the second Z-axis sensor;
Speed control for exciting the first Z-axis coil and the second Z-axis coil based on the measured values of the first Z-axis sensor and the second Z-axis sensor to control the Z-direction speed of the slider portion. Means,
The XY stage according to claim 1, wherein the XY stage is provided.   The slider portion moves on the lattice platen, and the length of the core facing the lattice platen in the first and second Z-axis coils is selected to be an integral multiple of the lattice pitch of the lattice platen. The XY stage according to any one of claims 1 to 7, characterized in that   The XY stage according to any one of claims 1 to 8, wherein the first and second Z-axis sensors are servo accelerometers.   The XY stage according to any one of claims 1 to 8, wherein the first and second Z-axis sensors measure an electromotive force generated in a coil. The XY stage according to claim 1, wherein the first and second Z-axis sensors measure an electromotive force generated in the piezoelectric element.

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