JP2013108939A - Stage mechanism and driving method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stage mechanism capable of achieving a long stroke drive relating to three degrees of freedom of XY directions and a yaw rotation direction and a fine drive in Z/pitch/roll directions by a compact actuator system constituted of a micro heater array built in a fixed base surface for mounting a stage, and to provide a driving method thereof.SOLUTION: A plurality of first-layer heaters 3 for protruding the surface of a base 2 by thermal deformation are disposed in an XY-directional array state, near the surface of the base 2 that comes into contact with a stage 1. At a part deeper from the surface of the base 2, a plurality of second-layer heaters 4 are disposed in an XY-directional array state so as to sandwich the front/rear/left/right of the first-layer heaters 3. A stage mechanism drives the stage 1 that comes into contact with thermal deformation protrusion parts protruded by the first-layer heaters 3, in an XYθ direction by causing the second-layer heaters 4 to move the thermal deformation protrusion parts in the XY direction.

Description

  The present invention relates to a stage mechanism in which a moving stage is mounted on a fixed base and a driving method thereof.

  In mechatronics equipment and the like that require precise positioning, the size of the apparatus is being reduced, and the stage used is also required to be downsized. In addition to the downsizing, demands for higher positioning accuracy and more freedom are increasing.

  Conventionally, a rotary electric motor, a magnetic linear motor, or the like is generally used as an actuator for driving a stage, and a PZT (piezoelectric element) actuator is sometimes used for ultra-precision positioning. Further, recently, application of a stage using a frictional driving force such as an ultrasonic motor stage and a surface acoustic wave linear motor has been advanced (for example, see Patent Document 1).

  A rotary electric motor achieves positioning in combination with a ball screw. While long stroke positioning is possible, the positioning resolution is not very high and may be used in combination with PZT actuators. In addition, the magnetic linear motor can be positioned with two degrees of freedom by adopting a planar configuration. Some PZT actuators can be driven in three axial directions by a single actuator. While the positioning resolution is high, the resulting stroke is short. Many ultrasonic motors use PZT, and a high positioning resolution is obtained with a long stroke (see, for example, Non-Patent Documents 1 and 2).

JP-A-7-177767

T. Yamaguchi et al., "Wear Mode Control of Drive Tip of Ultrasonic Motor for Precision Positioning", Wear, 2003, Vol. 256, pp.145-152 N. Osakabe et al., "Surface acoustic wave linear motor using siliconslider", Proc. Of IEEE Workshop on Micro Electro Mechanical Systems, Heidelberg, 1998 Jan., p.25-29

  In a stage using a conventional actuator, it is usually necessary to combine a plurality of actuators in order to realize stage driving with multiple degrees of freedom. Basically, the degree of freedom of motion of a rigid body in space is 6 degrees of freedom that combines translational motion in the X / Y / Z axis direction and rotational motion (pitch, roll, yaw) around these axes. . When realizing this 6-degree-of-freedom drive on a precision stage, some actuators can be driven with multiple degrees of freedom, but generally a plurality of actuators are combined, so that the system becomes large.

  On the other hand, for example, in a zoom lens driving mechanism of a digital camera and a fine movement stage of various microscopes, considering the spatial restrictions of the apparatus and the weight of the stage mounted product being small, the configuration is as compact as possible and has a high degree of freedom and high flexibility. A multi-degree-of-freedom stage mechanism using an actuator that realizes accurate positioning is desired.

  The present invention has been made paying attention to such problems, and is a compact actuator system composed of a microheater array incorporated on the surface of a fixed base on which a stage is mounted, and has three degrees of freedom in the XY direction and the yaw rotation direction. It is an object of the present invention to provide a stage mechanism capable of realizing long stroke driving and fine driving in the Z / pitch / roll direction, and a driving method thereof.

  The stage mechanism according to the present invention is a stage mechanism in which a moving stage is mounted on a fixed base, and a first layer for thermal deformation protrusion of the surface of the fixed base in the vicinity of the surface of the fixed base that contacts the moving stage. A plurality of heaters are arranged in an array in the X and Y directions, and a plurality of heaters in the second layer are arranged in an X and Y direction so as to sandwich the front, rear, left and right of the first layer heater deep from the fixed base surface. And the second layer heater is configured to move the thermal deformation protrusion by the first layer heater in the XY direction and drive the moving stage in contact with the thermal deformation protrusion in the XYθ direction. It is characterized by being.

  Further, the stage mechanism driving method according to the present invention is a stage mechanism driving method for driving the stage mechanism according to the present invention, wherein at least two rows of the first layer heaters that are spaced apart and parallel to each other. The first layer heater of the first group is driven, the moving stage is lifted by the thermal deformation protrusion, and then the second layer of the first group sandwiching the first layer heater of the first group A first step of driving an eye heater, moving the thermal deformation protrusion in the X or Y direction, and moving the moving stage in contact with the thermal deformation protrusion in the X or Y direction; Driving at least two rows of the second group of first group heaters, which are different from the first layer heaters, in parallel and spaced apart from each other, bringing the thermal deformation protrusions into contact with the moving stage, Turn off the heater of the first layer, and then the first layer of the second group Driving the second group of second layer heaters sandwiching the heater of the second group, and moving the heat deformation protrusions by the second group of first layer heaters in the X or Y direction, The first step and the second step are repeated.

  The stage mechanism driving method according to the present invention is a stage mechanism driving method for driving the stage mechanism according to the present invention, wherein at least three of the heaters of the first layer that are not in a straight line are provided. The first layer heater of the first group is driven, the moving stage is lifted by the thermal deformation protrusion, and then the second layer of the first group sandwiching the first layer heater of the first group And the first step of moving the thermal deformation protrusion in the rotational direction around the central axis of the moving stage, and the first group of first layer heaters different from each other, at least not in a straight line Drive the heaters of the first layer of the second group at three or more locations, bring the thermal deformation protrusions into contact with the moving stage, turn off the heaters of the first layer of the first group, Second group second layer sandwiching second group first layer heater And a second step of moving the thermal deformation protrusion by the first layer heater of the second group in a rotational direction around the central axis of the moving stage, and the first step and The second step may be repeated.

  According to the present invention, long stroke rotation control in the yaw direction is also possible by emphasizing control of the heater groups arranged in an array. Furthermore, since fine movement adjustment in the height direction is possible by thermal protrusion, fine movement positioning in the Z / pitch / roll direction is also possible. That is, a 6-degree-of-freedom stage drive is possible with one microheater array. The first layer heater for thermal deformation protrusion of the base surface is arranged near the base surface of the stage, and the second layer heater is arranged so as to sandwich the top, bottom, left and right of the first layer heater in a deeper place, Let this be one heater group. The second layer heater is for driving in the X and Y directions of the thermal deformation protrusion by the first layer heater. This heater group is arranged in an array in the XY direction of the base surface. At the start of driving the stage, first, the first layer heater generates a thermal deformation protrusion, which is brought into contact with the stage. In this state, the heater of the second layer is heated and the protrusion is moved in the plane direction. As the second layer heater, a heater to be heated is selected depending on the driving direction. The stage is driven in the direction along with the protrusion. When the stroke reaches the limit, stop heating the heater and retract the protrusion. By repeating this cycle, long stroke driving in the XY directions is realized.

  Thus, according to the present invention, in a compact actuator system composed of a microheater array incorporated on the surface of a fixed base on which a stage is mounted, a long stroke drive for three degrees of freedom in the XY direction and the yaw rotation direction, and Z A stage mechanism capable of realizing fine driving in the / pitch / roll direction and its driving method can be provided.

It is (a) perspective view, (b) top view, (c) side view of the stage mechanism of 1st embodiment concerning this invention. It is the schematic of the system which controls the stage mechanism shown in FIG. FIG. 6 is a plan view and a side view showing operations of a first layer heater and a second layer heater when the stage is moved in the X-axis direction by the stage mechanism shown in FIG. 1. It is a side view which shows the finite element model which modeled the heater and base of the 1st layer of the stage mechanism shown in FIG. 5A is a perspective view of a three-dimensional shape of a base surface protrusion calculated using the finite element model shown in FIG. 4, and FIG. 5B is a graph showing a cross-sectional shape of the protrusion portion. It is a side view showing operation | movement of the heater of the 1st layer when a stage is finely moved to a Z-axis direction by the stage mechanism shown in FIG. It is a side view showing operation | movement of the heater of the 1st layer when implementing the pitch and roll control of a stage with the stage mechanism shown in FIG. It is a top view showing operation | movement of the heater of the 1st layer and the 2nd layer when implementing the yaw control of a stage by the stage mechanism shown in FIG. It is (a) top view of the stage mechanism of 2nd embodiment concerning this invention, (c) It is a side view.

  A first embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic view of a stage mechanism used in the first embodiment according to the present invention. FIG. 1A is an overhead view of the stage mechanism, and the stage mechanism includes a base (fixed base) 2 and a stage (moving stage) 1. FIG. 1B is a schematic view of the base 2 and the inside thereof as seen from the mounting surface of the stage 1. The first-layer heaters 3 are arranged in an array, and the second-layer heaters 4 are also arranged in an array so that the first-layer heaters 3 are sandwiched from four sides. The first layer heater 3 and the second layer heater 4 are both incorporated in the vicinity of the surface layer of the base 2, and the first layer heater 3 is more base 2 than the second layer heater 4. Place it so that it is close to the surface. FIG. 1C is a schematic diagram showing the positional relationship between the stage 1, the base 2, and the heaters 3 and 4 when the stage mechanism is viewed from the side. Bumps 5 may be provided on the surface of the stage 1 and the surface of the base 2 in order to prevent sticking depending on the surface state.

  FIG. 2 shows an outline of a stage system for driving the stage mechanism of FIG. In the present invention, the stage 1 mounted on the base 2 is moved by independently controlling the heaters 3 and 4 arranged in an array. Therefore, driving amplifiers (Amplifiers) 8 and 9 are arranged for the respective heaters 3 and 4. A digital signal from a controller (Controller) 6 is converted into an analog signal by a D / A converter (D / A converter) 7, and the base 2 passes through a heater amplifier 8 for the first layer and a heater amplifier 9 for the second layer. Electric power is supplied to each of the heaters 3 and 4. Also, the position of the three axes in the X, Y, and Z directions of the stage 1 and the posture positions of the pitch, roll, and yaw are detected by the position sensor / position detection sensors X, Y, Z-axis, Pitch, Roll, Yaw. (motion sensor) 10 may be used, and this signal may be fed back and used for control.

  FIG. 3 is a schematic diagram showing the operation of the first layer heater 3 and the second layer heater 4 when the stage 1 is moved in the X-axis direction by the stage mechanism of FIG. Hereinafter, the heater 3 in the first layer is referred to as a surface protrusion heater 3, and the heater 4 in the second layer is referred to as a protrusion movement heater 4. Here, a heater group in which the first layer heater 3 is surrounded by the second layer heater 4 is defined as one heater group, and this heater group is arranged in the four group base. The arrangement is not limited to this, and the arrangement and number of heater groups are not limited to this.

  Here, consider a case where the stage 1 is moved in the positive X-axis direction. First, as shown in FIG. 3, among the protrusion movement heaters, electric power is applied to the protrusion movement heater 4 arranged on the right side of the surface protrusion heater 3, and the surface expansion heater 3 is made negative in the X-axis by its thermal expansion. Move in the direction (step A). Next, in a state where electric power is applied to the protrusion moving heater 4, electric power is applied to the surface protrusion heater 3 to form the heat deformation protrusion 11 by the first layer heater 3 to protrude the surface of the base 2, The stage 1 is lifted from the surface of the base 2 (step B). In this state, power supply to the protrusion movement heater 4 disposed on the right side of the front surface protrusion heater 3 is stopped, and power supply to the protrusion movement heater 4 disposed on the left side of the surface protrusion heater 3 is started ( Step C). Thereafter, the power supply to the surface protrusion heater 3 is stopped in a state where electric power is applied to the protrusion movement heater 4 arranged on the left side of the surface protrusion heater 3 (step D). As described above, the stage 1 mounted on the base 2 can move in the positive direction of the X-axis by the stage movement amount 12 (Δd), with a series of operations from Step A to Step D as one stroke. If it is desired to move the stage 1 larger than Δd, this operation may be repeated. When fine positioning within one stroke is desired, positioning can be performed by adjusting the power supply to the protrusion moving heater 4 in the state of Steps B to C. Similarly, when the stage 1 is driven in the negative X-axis direction or when it is desired to drive in the Y-axis direction, the stage movement and fine positioning can be performed by supplying power to the protrusion moving heater 4. Become.

  In the present invention, the stage is driven by causing the surface of the base 2 to protrude by the heater 3 of the first layer. For this reason, the protrusion of the surface of the base 2 requires at least a protrusion height larger than the surface roughness of the surface of the base 2 and the surface of the stage 1. Therefore, using a finite element model in which the first layer heater 3 and the base 2 are modeled in the arrangement shown in FIG. 4, the amount of electric power and the protrusion height given to the first layer heater 3 by heat transfer simulation are used. Evaluated the relationship.

  FIG. 5 shows the three-dimensional shape of the protruding shape simulation result of the surface of the base 2 by the first layer heater 3 and the cross-sectional shape of the protruding portion obtained by the simple simulation. In this simulation, the distance d from the surface of the base 2 to the first layer heater 3 was set to 10 μm. It can be seen that the protrusion height changes depending on the electric power applied to the heater 3 of the first layer, and it is possible to obtain a higher protrusion shape with a larger electric power. For example, it is understood that a protrusion height of 100 nm or more can be obtained when power of about 50 mW is applied. Therefore, it is considered that the stage 1 can be sufficiently lifted from the surface of the base 2 by setting the roughness of the surface of the base 2 and the surface of the stage 1 to, for example, Ra = 0.01 μm.

  Next, consider a case where stage positioning is performed in the Z-axis direction. FIG. 6 is a schematic diagram showing the operation of the first layer heater 3 when the stage 1 is finely positioned in the Z-axis direction by the stage mechanism of FIG. By adjusting the amount of electric power applied to the surface protrusion heater 3 and changing the height of the protrusion, the stage 1 can be finely positioned in the Z-axis direction.

  At this time, a fine movement positioning of the pitch posture and roll posture of the stage 1 becomes possible by giving a difference in the amount of electric power given to each surface protrusion heater 3. FIG. 7 is a schematic diagram showing the operation of the heater 3 of the first layer when the pitch / roll control of the stage 1 is performed by the stage mechanism of FIG. In the group of heaters arranged side by side in the X direction, the posture (roll posture) around the Y axis can be finely adjusted by making a difference in the amount of electric power applied to the surface protrusion heater 3. Similarly, in the heater group arranged side by side in the Y direction, the attitude around the X axis (pitch attitude) can be finely adjusted by making a difference in the amount of electric power applied to the surface protrusion heater 3.

  Next, consider a case where the stage is rotated in the Z-axis rotation direction (yaw attitude). FIG. 8 is a schematic diagram showing the operation of the first layer heater 3 and the second layer heater 4 when the yaw control of the stage 1 is performed by the stage mechanism of FIG. By performing cooperative control of the heater groups arranged in an array in the XY direction in the same manner as the movement in the X-axis direction, a fine rotation of Δθ per step about the Z-axis can be realized.

  As described above, coordinated control of the heater groups arranged in an array on the surface of the base 2 allows stage movement / rotation in the XYθ direction (θ: rotation around the Z axis), fine positioning in the Z axis direction, pitch -Fine rotation positioning in the roll direction can be realized.

  A second embodiment according to the present invention will be described with reference to FIG. FIG. 9 is a schematic view of a stage mechanism used in the second embodiment according to the present invention. The stage mechanism of the second embodiment is basically the same as the stage mechanism shown in the first embodiment, but the contact pad is placed on the base 2 where the first layer heater 3 is disposed. 13 is characteristic. The height of the contact pad 13 is set to be lower than that of the bump 5 separately provided on the base. When the position d from the surface of the base 2 to the first layer heater 3 is small when the surface protrusion by the first layer heater 3 touches the stage 1, the heat generated by the first layer heater 3 is reduced. There is a risk that it will escape to the surface of the stage 1 and the protruding shape cannot be maintained. By disposing the contact pad 13 on the heater 3 of the first layer, the heat generated by the heater is prevented from escaping to the surface of the stage 1 and the surface roughness of the contact pad 13 is optimized. It is possible to suppress the variation in the driving force and to make the movement amount 12 (Δd) of the stage 1 per stroke constant.

  By using the present invention, a compact actuator system composed of a micro heater array incorporated on the surface of a fixed base on which a moving stage is mounted allows a long stroke drive for three degrees of freedom in the XY direction and the yaw rotation direction, and Z / pitch / Fine driving in the roll direction is possible. In addition, by applying the principle of the present invention, it is possible to simultaneously move a plurality of objects mounted on the same base in different directions. For example, when applied to a stage of a microscope, the object is placed on the stage within the field of view of the microscope. There is a possibility that it can be realized to move and observe individual cells.

1 Stage 2 Base 3 1st layer heater (heater for surface protrusion)
4 Second layer heater (protruding movement heater)
5 Bump 6 Controller 7 D / A converter 8 First layer heater amplifier 9 Second layer heater amplifier 10 Stage position / orientation detection sensor 11 Thermal deformation protrusion by first layer heater 12 Stage movement amount 13 Contact pad

Claims (3)

  In a stage mechanism in which a moving stage is mounted on a fixed base, a first layer heater for protruding heat deformation on the surface of the fixed base is arranged in an XY direction in the vicinity of the surface of the fixed base that contacts the moving stage. A plurality of second layer heaters are arranged in an array in the XY direction so as to sandwich the front, rear, left and right of the first layer heater deeply from the surface of the fixed base, and the second layer The heater is configured to move in the XY direction the thermal deformation protrusion by the first layer heater and to drive the moving stage in contact with the thermal deformation protrusion in the XYθ direction. Stage mechanism. A stage mechanism driving method for driving the stage mechanism according to claim 1,
Among the first layer heaters, at least two rows of first group heaters that are spaced apart and parallel to each other are driven, and the moving stage is lifted by the thermal deformation protrusions, Driving the first-layer second layer heater sandwiching the first-layer heater of the group, moving the thermal deformation protrusion in the X or Y direction, and contacting the moving stage in contact with the heat deformation protrusion A first step of moving in the X or Y direction;
Driving at least two rows of the second group of first group heaters, which are different from the first group of first layer heaters, in contact with each other, bringing the thermal deformation protrusions into contact with the moving stage, Turn off the first layer heater of the first group, and then drive the second group of second layer heaters sandwiching the second group of first layer heaters, A second step of moving the thermal deformation protrusion by the first layer heater in the X or Y direction,
A method for driving a stage mechanism, wherein the first step and the second step are repeated. A stage mechanism driving method for driving the stage mechanism according to claim 1,
Among the heaters of the first layer, drive at least three first layer heaters of the first group that are not in a straight line, lift the moving stage by the thermal deformation protrusions, Driving a first group of second layer heaters sandwiching a group of first layer heaters, and moving the thermal deformation protrusion in a rotational direction around a central axis of the moving stage;
Different from the first-layer heater of the first group, at least three or more second-layer first-layer heaters that are not in a straight line are driven, and the thermal deformation protrusions are brought into contact with the moving stage. The first group heater of the first group is turned off, and then the second group heater of the second group sandwiching the first group heater of the second group is driven, and the second group of heaters is driven. A second step of moving the thermal deformation protrusion by the heater of the first layer in the rotational direction around the central axis of the moving stage,
A method for driving a stage mechanism, wherein the first step and the second step are repeated.