CN105278255A - Noncontact six-degree-of-freedom positioning device and method for magnetic levitation planar motor - Google Patents

Abstract

The invention relates to a noncontact six-degree-of-freedom positioning device and method for a magnetic levitation planar motor. The device and the method provided by the invention comprise the processes as follows: a cartesian coordinate system is built on a mover of the magnetic levitation planar motor; a first laser interference measurement device is arranged in an X-axis direction of the cartesian coordinate system; a second laser interference measurement device is arranged in a Y-axis of the cartesian coordinate system; a reflector is arranged on the mover of the magnetic levitation planar motor; a plurality of eddy current transducers are also arranged on the mover of the magnetic levitation planar motor; a horizontal aluminum plate is pasted to the upper surface of a stator of the magnetic levitation planar motor; data are measured through the laser interference measurement devices and the eddy current transducers; and an operation is carried out to obtain a result. Six-degree-of-freedom noncontact position detection device and method applied to a long-stroke magnetic levitation planar motor mover provided by the invention can achieve a long-stroke distance measurement, and is relatively small in interference of external factors, simple in structure and relatively high in accuracy.

Description

A kind of levitation planar motor non-contact six-degree of freedom locating device and method

Technical field

The present invention relates to a kind of levitation planar motor non-contact six-degree of freedom locating device and method.

Background technology

Levitation planar motor greatly can simplify planar motion mechanism, alleviates moving-mass, and realizing without friction, without the micron accuracies high-speed motion worn and torn, is the focus of current large travel high-speed precise flange systematic study.Broad prospect is particularly had in IC litho machine field.As shown in Figure 1, levitation planar motor comprises mover (1 ') and stator (2 ') to the structural representation of levitation planar motor.The structure that levitation planar motor is succinct effectively prevent elastic deformation that transmission link in conventional motors drive system exists, there is the bad phenomenon such as the motion delay that friction force brings because of holding components, the tracking error brought because kinematic train is delayed when decreasing moving interpolation, the stability of lifter motion system and positioning precision.And the revolutionary structural design of itself also makes to be that the double-workbench of a difficult problem is exchangeed problem and simplified originally.The time consumption problem throughput rate is improved about 35% that double-workpiece-table litho machine solves that focusing and leveling and calibration accuracy produce, but double-workpiece-table litho machine is the worktable adopting " H " type linear electric motors to drive, complicated physical construction brings a difficult problem for structural design and Motion trajectory to the problem that double-workbench exchanges.And the succinct physical construction of levitation planar motor significantly reduces the difficulty of double-workbench exchange system structure and controlling planning design.Further, because significantly alleviating of mover moving-mass makes motor working efficiency obtain tremendous raising.Compared with adopting H bridge type kinematic system litho machine with tradition, have employed levitation planar motor TwinscanNXT1950I workbench of lithography machine acceleration is increased to 15g from 8g, movement velocity is increased to 3.2m/s from 2.4m/s, kinematic accuracy reaches 1.5nm, productive rate reach 175 silicon chips/hour, production efficiency and quality obtain significant increase.On the other hand, levitation planar motor can work under vacuum conditions.Employing optical wavelength is the extreme UV light source (ExtremeUltraVioletLithography of 10-14nm, the technology of EUVL) carrying out the photoetching of IC chip is suggested as the development trend of Next Generation Lithography, photoetching resolution can be promoted to 10nm rank by the employing of EUVL, EUVL photoetching has become microelectronic manufacturing technology study hotspot, the extreme ultraviolet of 13.5nm wavelength is easily absorbed by air molecule, thus be can carry out work under vacuum conditions to worktable requirement, traditional air-flotation workbench that " H " type linear electric motors adopt cannot meet extreme ultra violet lithography rigors, levitation planar motor eliminates complicated huge H bridge type kinematic system and air-float guide rail, worktable is worked under vacuum conditions.

In sum, adopt the levitation planar motor of iron-free formula permanent magnet array manufacture as worktable, except can the transmission stiffness of lifter motion system, except the property control performance energy such as control accuracy and dynamic responding speed, and owing to there is not magnetic resistance suction, can suspend work under vacuum conditions completely.The performance that levitation planar motor is superior obtains domestic and international academia and pays close attention to widely.Because levitation planar motor is 6DOF suspended motion, need to carry out 6DOF non-contact precision location survey to mover.Positioning measurment system provides position to feed back for kinetic control system, and high-precision motion controls to depend on high-accuracy position system.Therefore how accurate 6DOF is carried out to levitation planar motor mover and be positioned in levitation planar motor motion control most important.

Existing multiple sensors is applied to precision measurement, and comprise grating scale, capacitive transducer, laser range sensor, current vortex sensor, laser interferometry system and linear hall sensor etc., various kinds of sensors specificity analysis is as follows:

1) grating scale: grating scale is widely used in high-precision large-stroke straight-line displacement and measures, Measurement Resolution can reach Subnano-class, the employing state-of-the-art technology grating scale resolution that ASML releases even reaches nanoscale, but due to grating scale employing is contact type measurement, be applied to the electric mover suspended completely interior directly destruction motor dynamics model, also destroy mover freedom of motion, cause Electric Machine Control to lose efficacy.

2) capacitive transducer: capacitive transducer calculates measuring distance by checking self and measuring electric capacity between thing, there is the features such as measuring accuracy is high, expensive, but because its measuring distance is little, cannot be applied to Long Distances range observation, and measured target surfaceness directly affects the precision of measurement result.

3) laser range sensor: this sensor design principle, based on the range of triangle method of optics, has micron-sized resolution, but due to range section, Long Distances motion cannot be applied to.

4) current vortex sensor: current vortex sensor has good frequency response characteristic, resolution can reach 1 micron, can be used for segment distance displacement measurement, but interference can be caused to its measurement result as the external condition such as alternating magnetic field, environment temperature, bit shift compensation need be carried out to result.

5) laser interferometry system: laser interferometry system is applied to litho machine Long Distances displacement measurement more, there is high response, high stability, high-resolution feature, be the ideal equipment that large range nanometer grade is measured, but it is expensive, system architecture is complicated.

6) linear hall sensor: a kind of sensor measuring flux density value made according to Hall effect, can determine the phase value of sensor and magnetic field distance or residing periodic magnetic field according to Distribution of Magnetic Field analytic model.But due to the impact of the factor such as manufacturing process, spatial magnetic field not in full conformity with analytic model result of calculation, thus error is caused to Hall element actual measured results.

Due to the various deficiencies that above-mentioned technological means exists, also do not have one can not destroy mover freedom of motion in existing technology, Long Distances range observation can be realized, less by extraneous factor interference, the simple expense of structure is lower, and the precision measurement method that precision is higher.

Summary of the invention

Goal of the invention of the present invention is the limitation solving above-mentioned existing planar motor method for detecting position, there is provided one can realize Long Distances range observation, less by extraneous factor interference, structure is simple, and the higher six degree of freedom non-contacting position pick-up unit being applied to Long Distances levitation planar motor mover of precision and method.

The present invention includes mover and the stator of levitation planar motor, the mover of levitation planar motor sets up cartesian coordinate system, the X-direction of described cartesian coordinate system arranges the first laser-interfering measurement device, the Y direction of described cartesian coordinate system arranges the second laser-interfering measurement device 2.2, the mover of described levitation planar motor arranges reflective mirror; The mover of described levitation planar motor also arranges some eddy current sensors, the aluminium sheet of the level that is sticked at the stator upper surface of levitation planar motor.

As preferably, the quantity of described eddy current sensor is 4, is arranged symmetrically in respectively on four angles of the mover of described levitation planar motor.

As preferably, the thickness of described aluminium sheet is less than 1mm.Because space magnetic flux density with permanent magnet array distance exponentially secondary decay, aluminium plate thickness is crossed conference and is caused coil and permanent magnet array apart from excessive, residing for coil space magnetic flux density reduce, energy consumption of electrical machinery increase, preferred thickness is less than the aluminium sheet of 11mm herein.

Measuring method of the present invention comprises the steps:

1) the first laser-interfering measurement device described in sends three light beams to three positions on the mover surface of levitation planar motor to carry out laser interferometry and obtains corresponding position data X1, X2, X3, and to define X1 and X3 distance be in the X-axis direction C _x, distance is in the Y-axis direction C _y; The second described laser-interfering measurement device sends light beam to three positions on the mover surface of levitation planar motor to carry out laser interferometry and obtains corresponding position data Y1, Y2, Y3, and to define Y1 and Y3 distance be in the X-axis direction A _x, distance is in the Y-axis direction A _y;

2) according to the data that step 1 records, the displacement in mover X-direction is calculated ^mx _owwith the anglec of rotation around Z axis in X-direction ^mφ _zx, the displacement in Y direction ^my _owwith the anglec of rotation around Z axis in Y direction ^mφ _zy, mover is around the anglec of rotation of X-axis ^mφ _x, and mover is around the anglec of rotation of Y-axis ^mφ _y, computing formula is as follows:

$X_{\mathrm{ow}}^m=\frac{X1+X3}{2}$

$Y_{\mathrm{ow}}^m=\frac{Y1+Y3}{2}$

$\sin \mathrm{\φ}_x^m=(-Y2+\frac{Y1+Y3}{2})/A_y$

$\sin \mathrm{\φ}_y^m=(-X2+\frac{X1+X3}{2})/A_x$

sin ^mφ _zx＝(X3-X1)/C _x

sin ^mφ _zy＝(Y3-Y1)/C _y；

3) by the distance between the eddy current sensor described in described vortex sensor measuring and described aluminium sheet, thus obtain each measured value, then the average getting measured value obtains mover displacement in the Z-axis direction ^mz _ow;

After adopting above structure, the present invention compared with prior art, has the following advantages:

It is 150mm/s that the present invention's a kind of levitation planar motor non-contact six-degree of freedom locating device and method can realize the mover maximum movement speed of levitation planar motor, positioning precision is a μm rank, rotating distance measurement range is that-1mrad is to 1mrad, tangential movement stroke is the high-acruracy survey of more than 300mm, and contactlessly can carry out six degree of freedom synchro measure, and not by external interference; The present invention does not destroy mover freedom of motion, can realize Long Distances range observation, and less by extraneous factor interference, the simple expense of structure is lower.

Accompanying drawing explanation

Fig. 1 is the structural representation of levitation planar motor in prior art.

Fig. 2 is laser interferometry schematic diagram of the present invention.

Fig. 3 is the X axis schematic diagram of Fig. 2.

Fig. 4 is the Y-axis schematic diagram of Fig. 2.

Fig. 5 is eddy current displacement instrumentation plan of the present invention.

Fig. 6 is structural representation of the present invention.

Shown in figure 1, mover, the 2.1, first laser-interfering measurement device, the 2.2, second laser-interfering measurement device, 3, reflective mirror, 4, eddy current sensor, 5, aluminium sheet.

Embodiment

Below in conjunction with the drawings and specific embodiments, the invention will be further described.

The present invention the present invention includes mover 1 and the stator of levitation planar motor as Figure 2-3, the mover 1 of levitation planar motor sets up cartesian coordinate system, the X-direction of described cartesian coordinate system arranges the first laser-interfering measurement device 2.1, the Y direction of described cartesian coordinate system arranges the second laser-interfering measurement device 2.2, the mover 1 of described levitation planar motor arranges reflective mirror 3; The mover 1 of described levitation planar motor also arranges some eddy current sensors 4, the aluminium sheet 5 of the level that is sticked at the stator upper surface of levitation planar motor.The quantity of described eddy current sensor 4 is 4, is arranged symmetrically in respectively on four angles of the mover 1 of described levitation planar motor.The thickness of described aluminium sheet is less than 1mm.

Measuring method of the present invention comprises the steps:

1) the first laser-interfering measurement device 2.1 described in sends three light beams to three positions on mover 1 surface of levitation planar motor to carry out laser interferometry and obtains corresponding position data X1, X2, X3, and to define X1 and X3 distance be in the X-axis direction C _x, distance is in the Y-axis direction C _y; The second described laser-interfering measurement device 2.2 sends light beam to three positions on mover 1 surface of levitation planar motor to carry out laser interferometry and obtains corresponding position data Y1, Y2, Y3, and to define Y1 and Y3 distance be in the X-axis direction A _x, distance is in the Y-axis direction A _y;

2) according to the data that step 1 records, the displacement on mover 1X direction of principal axis is calculated ^mx _owwith the anglec of rotation around Z axis in X-direction ^mφ _zx, the displacement in Y direction ^my _owwith the anglec of rotation around Z axis in Y direction ^mφ _zy, mover 1 is around the anglec of rotation of X-axis ^mφ _x, and mover 1 is around the anglec of rotation of Y-axis ^mφ _y, computing formula is as follows:

$X_{\mathrm{ow}}^m=\frac{X1+X3}{2}$

$Y_{\mathrm{ow}}^m=\frac{Y1+Y3}{2}$

$\sin \mathrm{\φ}_x^m=(-Y2+\frac{Y1+Y3}{2})/A_y$

$\sin \mathrm{\φ}_y^m=(-X2+\frac{X1+X3}{2})/A_x$

sin ^mφ _zx＝(X3-X1)/C _x

sin ^mφ _zy＝(Y3-Y1)/C _y；

4) measure the distance between described eddy current sensor 4 and described aluminium sheet 5 by described eddy current sensor 4, thus obtain each measured value, then the average getting measured value obtains mover 1 displacement in the Z-axis direction ^mz _ow;

Further, due to the sin φ ≈ φ when corner φ goes to zero, then above-mentioned formula can be reduced to:

$\mathrm{\φ}_x^m=(-Y2+\frac{Y1+Y3}{2})/A_y$

$\mathrm{\φ}_y^m=(-X2+\frac{X1+X3}{2})/A_x$

^mφ _zx＝(X3-X1)/C _x

^mφ _zy＝(Y3-Y1)/C _y

$\mathrm{\φ}_z^m=\frac{1}{2}(\mathrm{\φ}_{\mathrm{zx}}^m+\mathrm{\φ}_{\mathrm{zy}}^m)$

The present invention is 4 with the quantity of eddy current sensor 4, and for example is illustrated on four angles being arranged symmetrically in the mover 1 of described levitation planar motor respectively, measured value is described eddy current sensor 4 and the distance of described aluminium sheet 5.For improving Z-direction measuring accuracy, adopt four eddy current sensors 4 symmetrical at mover 1 four angles, as seen in figs. 5-6.Z _ecs1, Z _ecs2, Z _ecs3, Z _ecs4be respectively the measured value of four eddy current sensors 4, under surving coordinate system, mover 1 is in conjunction with center displacement in a z-direction: can use formula $Z_{\mathrm{ow}}^m=\frac{1}{4}(Z_{\mathrm{ecs}1}+Z_{\mathrm{ecs}2}+Z_{\mathrm{ecs}3}+Z_{\mathrm{ecs}4})$ Calculate.

Below only just most preferred embodiment of the present invention is described, but can not be interpreted as it is limitations on claims.The present invention is not limited only to above embodiment, and all various changes done in the protection domain of independent claims of the present invention are all in protection scope of the present invention.

Claims (4)

1. a levitation planar motor non-contact six-degree of freedom locating device, it is characterized in that: the mover (1) and the stator that comprise levitation planar motor, the mover (1) of levitation planar motor sets up cartesian coordinate system, the X-direction of described cartesian coordinate system arranges the first laser-interfering measurement device (2.1), the Y direction of described cartesian coordinate system arranges the second laser-interfering measurement device (2.2), the mover (1) of described levitation planar motor arranges reflective mirror (3); The mover (1) of described levitation planar motor also arranges some eddy current sensors (4), the aluminium sheet (5) of the level that is sticked at the stator upper surface of levitation planar motor.

2. a kind of levitation planar motor non-contact six-degree of freedom locating device according to claim 1, it is characterized in that: the quantity of described eddy current sensor (4) is 4, be arranged symmetrically in respectively on four angles of the mover (1) of described levitation planar motor.

3. a kind of levitation planar motor non-contact six-degree of freedom locating device according to claim 1, is characterized in that: the thickness of described aluminium sheet is less than 1mm.

4. adopt a measuring method for a kind of levitation planar motor non-contact six-degree of freedom locating device as claimed in claim 1, it is characterized in that, comprise the steps:

1) the first laser-interfering measurement device (2.1) described in sends three light beams to three positions on mover (1) surface of levitation planar motor to carry out laser interferometry and obtains corresponding position data X1, X2, X3, and to define X1 and X3 distance be in the X-axis direction C _x, distance is in the Y-axis direction C _y; Described the second laser-interfering measurement device (2.2) sends light beam to three positions on mover (1) surface of levitation planar motor to carry out laser interferometry and obtains corresponding position data Y1, Y2, Y3, and to define Y1 and Y3 distance be in the X-axis direction A _x, distance is in the Y-axis direction A _y;

2) according to the data that step 1 records, the displacement in mover (1) X-direction is calculated ^mx _owwith the anglec of rotation around Z axis in X-direction ^mφ _zx, the displacement in Y direction ^my _owwith the anglec of rotation around Z axis in Y direction ^mφ _zy, mover (1) is around the anglec of rotation of X-axis ^mφ _x, and mover (1) is around the anglec of rotation of Y-axis ^mφ _y, computing formula is as follows:

sin ^mφ _zx＝(X3-X1)/C _x

sin ^mφ _zy＝(Y3-Y1)/C _y；

3) by the distance between the eddy current sensor (4) described in the measurement of described eddy current sensor (4) and described aluminium sheet, thus obtain each measured value, then the average getting measured value obtains mover (1) displacement in the Z-axis direction ^mz _ow.