JP2011169818A - Sensor unit and positioning device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor unit which has an inexpensive and compact structure and can measure a large displacement exceeding a side long area of a gap sensor for a target position and a positioning device using the same. <P>SOLUTION: The sensor unit 100 for measuring a position of a target 110 from a detected physical quantity includes the target 110 having an inclined surface 116 with an inclination relative to a movable direction a and a direction b vertical thereto and the gap sensor 120 for detecting a physical quantity corresponding to a distance to the inclined surface 116. Thus, since the displacement of the inclined surface 116 to the gap sensor 120 is smaller than the displacement of the target 110 to the movable direction, the large displacement exceeding the side long area of the gap sensor 120 can be measured for the target position in a low-cost and compact constitution. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sensor unit for measuring the position of a target from a detected physical quantity and a positioning device using the sensor unit.

  2. Description of the Related Art Conventionally, as a displacement sensor used in a positioning device or the like, a capacitance sensor that uses a change in capacitance and an eddy current sensor that uses a change in impedance of a sensor coil are known. For example, in the fine movement stage device described in Patent Document 1, a capacitance type fine movement amount detection sensor is installed so as to face the end face of a substantially rectangular stage supported by a base. The stage is moved by the piezoelectric element while feeding back the fine movement amount detection result.

  In addition, the electrostatic capacitance type tilt angle sensor described in Patent Document 2 is provided with a protective ring, an insulator, and a guard ring on a horizontal end surface, and a sensor electrode is provided in the guard ring. The sensor electrode is an electrode having a shape obtained by dividing a circle into four parts, and is composed of electrodes arranged so as to be symmetrical with respect to the x axis and the y axis. The four identically shaped electrodes (child sensors) of the guard ring, guard ring, and sensor are each insulated by an insulator, and by measuring the capacitance between the four electrodes and the target surface, The inclination of the sensor with respect to the target surface is measured.

  As described above, in the conventional configuration, the surface of the sensor head is maintained parallel to the target surface perpendicular to the direction of movement of the target. FIG. 4 is a plan view showing a configuration of a conventional positioning unit 900. As shown in FIG. 4, the target surface 916 of the target 910 that faces the sensor 920 is perpendicular to the movable direction of the target 910.

JP 2002-231790 A JP 2001-241948 A

  However, since the electrostatic capacitance sensor and the eddy current sensor as described above have a short measurement range, for example, when the movable region of the stage is larger than the measurement range of these sensors, the region cannot be covered. On the other hand, a displacement sensor having a long measurement range can be used, but the mechanism around the sensor becomes large and bulky. In addition, a sensor that can cover such a length measurement area is often expensive, and the cost increases.

  The present invention has been made in view of such circumstances, and a sensor unit capable of measuring a large displacement exceeding the length measurement range of a gap sensor with respect to a target position and a positioning device using the same with an inexpensive and compact configuration. The purpose is to provide.

  (1) In order to achieve the above object, a sensor unit of the present invention is a sensor unit that measures the position of a target from a detected physical quantity, and has an inclination with respect to a movable direction and a direction perpendicular thereto. It is characterized by comprising a target on which a surface is formed and a gap sensor for detecting a physical quantity corresponding to the distance from the inclined surface.

  Accordingly, since the displacement of the inclined surface toward the gap sensor with respect to the displacement in the moving direction of the target becomes small, a large displacement exceeding the length measurement range of the gap sensor can be measured with respect to the target position with an inexpensive and compact configuration.

  (2) Moreover, the sensor unit of this invention is further provided with the calculation part which calculates the position of the said target from the physical quantity corresponding to the distance with the said inclined surface. Thereby, the displacement of the target can be calculated from the change in physical quantity corresponding to the distance between the inclined surface and the gap sensor.

  (3) In the sensor unit of the present invention, the gap sensor can detect the physical quantity, has a probe surface having a diameter of 15 mm or less, and the inclined surface is inclined by 3 ° or more with respect to the movable direction. It is characterized by being formed at 30 ° or less. As a result, accurate displacement detection by an inexpensive and compact electrostatic capacity sensor or eddy current sensor can be utilized for measurement in a relatively large range. A length measurement range of about 20 μm to 30 mm can be realized. In particular, it is effective for measuring a displacement of 1.5 mm or more which is too large to be directly detected by a small capacitance sensor or eddy current sensor.

  (4) Further, the positioning device of the present invention includes the sensor unit having a stage as the target, a control unit that outputs a signal for driving control based on the calculated position of the target, and the output And a drive unit for driving the stage in accordance with the received signal. Thereby, a stage can be driven and positioned about a large drive range with a compact sensor.

  According to the present invention, a large displacement exceeding the length measurement range of the gap sensor can be measured with respect to the target position with an inexpensive and compact configuration.

It is a top view which shows the structure of the positioning unit concerning 1st Embodiment. It is a sectional side view which shows the structure of the positioning unit concerning 1st Embodiment. It is a plane sectional view showing the composition of the positioning device concerning a 2nd embodiment. It is a plane sectional view showing the composition of the positioning device concerning a 3rd embodiment. It is a top view which shows the structure of the conventional positioning unit.

  Next, embodiments of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference numerals are given to the same components in the respective drawings, and duplicate descriptions are omitted.

[First Embodiment]
FIG. 1A is a plan view showing the configuration of the positioning unit 100. The positioning unit 100 includes a stage 110 and a gap sensor 120, and measures the position of the stage 110 from the physical quantity detected by the gap sensor 120. The stage 110 includes a stage main body 112 and an inclined portion 115 (target), and is movable in a certain direction (movable direction a). The stage 110 is basically made of metal, but may be composed of, for example, a ceramic stage body 112 and a metal inclined portion 115. The inclined portion 115 is formed with an inclined surface 116 having a certain inclination with respect to the movable direction a and the direction b perpendicular thereto. The inclined portion 115 and the gap sensor 120 constitute a sensor unit 127.

  The gap sensor 120 detects a physical quantity corresponding to the distance from the inclined surface 116. As a result, the displacement of the inclined surface 116 toward the gap sensor 120 with respect to the displacement of the stage 110 in the movable direction becomes small, so that a large displacement exceeding the length measurement range of the gap sensor 120 can be measured for the position of the stage 110. Further, since the gap sensor 120 is usually inexpensive and small, the sensor unit 127 can be configured with an inexpensive and compact configuration.

Note that the magnification of the measurement area and the inclination of the inclined surface 116 with respect to the movable direction correspond as shown in the following table.

  Since such a correspondence exists, the gap sensor 120 has a probe surface formed with a diameter of 15 mm or less, and the inclined surface 116 is formed with an inclination of 3 ° or more and 30 ° or less with respect to the movable direction. It is preferable. The measurement range of the small gap sensor 120 is in the range of about 10 μm to 1.5 mm. However, with such a specification, the target position can be easily measured in the movable range of 20 μm to 30 mm. In particular, a movable range larger than 1.5 mm is a range that cannot be measured in the length measurement range of the small gap sensor 120 itself, and has a great effect. The probe surface is generally circular, but may have other shapes. In this case, the above-mentioned “diameter” means a width.

  The gap sensor 120 detects a physical quantity at the probe surface 125. The probe surface 125 is preferably parallel to the inclined surface 116. The physical quantity to be detected differs depending on the type of the gap sensor 120. For example, when the gap sensor 120 is a capacitance sensor or an eddy current sensor, it is a capacitance or an impedance, respectively. Further, in the case of a laser sensor or a light amount detection sensor, the laser detection position and the light amount, respectively.

  The gap sensor 120 is preferably a capacitance sensor or an eddy current sensor. In that case, since the distance to the target surface can be detected in the range of about 10 μm to 1.5 mm, if the inclination of the inclined surface 116 is adjusted, the position of the inclined portion 115 is measured within a movable range of 20 μm to 30 mm. it can. In particular, the movable range larger than 1.5 mm is a range that cannot be measured in the length measurement area of the small gap sensor 120 itself. Therefore, there is a remarkable effect that the displacement in this range can be measured. Capacitance sensors and eddy current sensors are inexpensive and compact, and can detect displacement precisely. This can be used for measurement in a relatively large range.

  The sensor unit 127 includes a calculation unit (not shown) that calculates the position of the inclined portion 115 from a physical quantity corresponding to the distance from the inclined surface 116. Thereby, the displacement of the inclined portion 115 can be calculated from the change in physical quantity corresponding to the distance between the inclined surface 116 and the probe surface 125. At this time, the coefficient for converting the signal representing the physical quantity into the displacement amount is derived from the inclination of the inclined surface 116 with respect to the movable direction. Further, in view of the configuration of the positioning unit 100, an error in measuring the position of the target may be taken into account, and calibration may be incorporated in the displacement calculation. Although the calculation unit may be attached to the positioning unit 100 as described above, the calculation unit may be incorporated into an entity that monitors the positioning unit 100 (for example, a feedback controller or a host computer).

  FIG. 1B is a side sectional view showing the configuration of the positioning unit 100. FIG. 1B shows a cross section when the target 110 is cut along the cross section A in FIG. 1A. The target 110 is supported by the base 130 via the ball 140 and can move in the movable direction a within a certain movable range.

  In the positioning unit 100, the gap sensor 120 changes the measurement target position in the inclined surface 116 as the target 210 moves, so that the flatness of the inclined surface 116 is small and the probe surface 125 (sensor head) is large. It is possible to measure with higher accuracy.

[Second Embodiment]
The positioning unit 100 described above can be applied to a positioning device. FIG. 2 is a plan sectional view showing the configuration of the positioning device 200. As shown in FIG. 2, the positioning device 200 includes a target main body portion 212, an inclined portion 215, a base portion 230, an actuator 250, and a gap sensor 120.

  The target main body 212 is elastically connected to the base body 230 by a hinge structure, and is movable with respect to the fixed base body 230. The target main body 212 has a pressure receiving surface 213, and moves in the pressing direction when the pressure receiving surface 213 receives the pressing force of the actuator 250, and moves in the opposite direction when the pressing force is released. In this case, the pressing direction of the actuator 250 is the moving direction of the target.

  A stage main body (not shown) is fixed to the upper surface of the target main body 212, and the stage main body moves in a movable direction in conjunction with the target main body 212 by driving the actuator 250. The target main body 212, the inclined portion 215, and the stage main body constitute a stage (target). In the positioning apparatus 200, the stage is a target as a position measurement target.

  The inclined portion 215 is connected to the pressing direction side of the target main body 212 and moves in conjunction with the target main body 212. An inclined surface 216 is formed on the inclined portion 215, and the inclined surface 216 faces the gap sensor 120. Thus, the inclined surface 216 is provided so as to intersect with the central axis direction of the actuator 250. By providing the inclined surface 216 at such a position, the inclination of the inclined surface 216 can be increased with respect to the movable direction a of the stage, and the position of the stage can be measured for a relatively small movable range. In the example of the sensor unit shown in FIG. 2, the inclination of the inclined surface 216 with respect to the movable direction a is 30 °, and at this time, the measurement range of the target displacement is twice the measurement range of the gap sensor 120.

  The base portion 230 fixes one end of the actuator 250. On the other hand, the movement of the target main body 212 is elastically limited by the hinge structure. The positioning device 200 further includes a control unit (not shown). The control unit feeds back the calculated stage position information and outputs a signal for drive control.

  The actuator 250 is driven according to the drive control signal output by the control unit, and presses the pressure receiving surface 213 with the tip 255. The opposite end of the tip 255 is fixed by the base 230, and the target main body 212 and the inclined portion 215 that have pressed the pressure receiving surface 213 move in the pressing direction. In this way, the actuator 250 drives the stage.

  The gap sensor 120 detects a physical quantity corresponding to the distance from the probe surface 125 to the inclined surface 216. Thereby, a stage can be driven and positioned about a large drive range with a compact sensor. The gap sensor 120 is preferably a capacitance sensor or an eddy current sensor.

  The positioning device 200 includes a calculation unit (not shown) that calculates the position of the target from a physical quantity corresponding to the distance from the inclined surface 216. Then, a target (stage) including the target main body 212 and the inclined portion 215, the gap sensor 120, and the calculation unit are gathered to constitute a sensor unit in the positioning device 200.

[Third Embodiment]
In the second embodiment, the inclined surface 216 is provided so as to intersect with the central axis direction of the actuator 250, but the inclined surface may be provided at a position not intersecting with the central axis direction of the actuator 250. FIG. 3 is a cross-sectional plan view showing the configuration of the positioning device 300 in which the inclined surface 316 is provided on the side surface of the target main body 312.

  As shown in FIG. 3, the positioning device 300 includes a target main body 312, a base body 330, an actuator 250, and a gap sensor 120. The target main body 312 is elastically connected to the fixed base portion 330 by a hinge structure, and is movable with respect to the base portion 330. The target main body 312 has a pressure receiving surface 313. The target main body 312 moves in the pressing direction when receiving the pressing force of the actuator 250 on the pressure receiving surface 313, and moves in the opposite direction when released from the pressing force.

  A stage main body (not shown) is fixed on the upper surface side of the target main body 312, and the stage main body can be moved in a movable direction in conjunction with the target main body 312 by driving an actuator. The target main body 312 and the stage main body form a stage (target).

  The inclined surface 316 is formed on the side surface of the target main body 312 and is provided at a position that does not intersect the central axis direction of the actuator 250. By providing the inclined surface 316 at such a position, the inclination of the inclined surface 316 can be reduced with respect to the movable direction of the stage, and the position of the stage can be measured over a large movable range. In the example of the sensor unit shown in FIG. 3, the inclination of the inclined surface 216 with respect to the movable direction is 3 °. At this time, the measurement range of the target displacement is 20 times the measurement range of the gap sensor 120.

  The base portion 330 fixes one end of the actuator 250. On the other hand, the movement of the target main body 312 is elastically limited by the hinge structure. The positioning device 300 further includes a control unit (not shown). The control unit outputs a signal for drive control based on the calculated position of the stage.

  The actuator 250 is driven according to the drive control signal output by the control unit, and presses the pressure receiving surface 313 with the tip 255. The opposite end of the tip 255 is fixed by the base portion 330, and the pressure receiving surface 313 is pressed to move the target main body 312 and the inclined surface 316 in the pressing direction. In this way, the actuator 250 drives the stage.

  The gap sensor 120 detects a physical quantity corresponding to the distance from the probe surface 125 to the inclined surface 316. The gap sensor 120 is preferably a capacitance sensor or an eddy current sensor. The positioning device 300 includes a calculation unit (not shown) that calculates the position of the target from a physical quantity corresponding to the distance from the inclined surface 316. The target (stage) including the target main body 312, the gap sensor 120, and the calculation unit constitute a sensor unit. In addition, the preferable aspect about the magnitude | size of the probe surface 125 of the gap sensor 120 and the flatness of the inclined surface 216 is the same as that of 2nd Embodiment.

  As described above, in the positioning devices 200 and 300, the gap sensor 120 has a probe surface formed with a diameter of 15 mm or less, and the inclined surfaces 216 and 316 have an inclination of 3 ° or more and 30 ° or less with respect to the movable direction a. It is preferable to be formed.

  In the above embodiment, the target is directly moved by the actuator. However, the above sensor unit can also be used when the target is moved using the enlargement displacement mechanism. In that case, the measurement of a displacement amount of, for example, about 300 to 500 μm is required as the enlarged displacement itself, but this can be directly measured.

  In the above embodiment, the sensor unit is used for the positioning device. However, the application range of the sensor unit is not limited to this, and adjustment of the lens of the microscope and the subtle of the stage of the semiconductor exposure apparatus It can also be applied to tilt adjustment.

100 Positioning unit 110 Stage 112 Stage body 115 Inclined portion (target)
116 Inclined surface 120 Gap sensor 125 Probe surface 127 Sensor unit 130 Base 140 Ball 200 Positioning device 210 Target 212 Target main body 213 Pressure receiving surface 216 Inclining surface 230 Base body 250 Actuator 255 Tip 300 Positioning device 312 Target main body 313 Pressure receiving surface 316 Inclining Surface 330 Base part a Movable direction b Direction perpendicular to the movable direction

Claims (4)

A sensor unit for measuring the position of a target from detected physical quantities,
A target on which an inclined surface having an inclination with respect to a movable direction and a direction perpendicular thereto is formed;
And a gap sensor for detecting a physical quantity corresponding to the distance to the inclined surface.   The sensor unit according to claim 1, further comprising a calculation unit that calculates a position of the target from a physical quantity corresponding to a distance from the inclined surface. The gap sensor can detect the physical quantity and has a probe surface formed with a diameter of 15 mm or less,
The sensor unit according to claim 1, wherein the inclined surface is formed with an inclination of 3 ° to 30 ° with respect to the movable direction. The sensor unit according to any one of claims 1 to 3, comprising a stage as the target.
A controller that outputs a signal for drive control based on the calculated target position;
A positioning apparatus comprising: a drive unit that drives the stage in accordance with the output signal.

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