CN102629122B - Long-stroke high-speed dual-drive nano positioning system - Google Patents

Abstract

The invention discloses a long-stroke high-speed dual-drive nano positioning system, which comprises a motion track instruction system (101), a master control computer (102), a PMAC motion control board (103), a servo motion control system (104), a positioning platform and a measurement control system (107), wherein the positioning platform comprises a macro motion platform (105) and a micro motion platform (106); triaxial measurement and triaxial control are taken into consideration in the nano positioning system so that precision control for X, Y1 and Y2 can be implemented, the positioning platform adopts a motion mode of 'long-stroke linear motor + short-stroke planar motor' and adopts master/slave control as motion control mode, the short-stroke planar motor is the target of master control, and feedback is measured by a laser interferometer to accomplish high-precision motion within a small range; and the long-stroke linear motor serves as a slave control system for the short-stroke motor, and feedback is measured by a grating scale to accomplish long-stroke high-speed gross motion. The response speed and real-time performances of the system are dramatically improved by means of motion decoupling for the planar motor and introduction of the PMAC motion control board.

Description

A kind of large travel high-speed double drive axis Nano-positioners

Technical field

The present invention relates to microelectronics specialized equipment technical field, particularly a kind of large travel high-speed double drive axis Nano-positioners, is particularly useful for advanced scanning projecting photoetching machine work stage subsystem.

Background technology

Large stroke, at a high speed, high-precision axis Nano-positioners occupies extremely important status in modern sophisticated industry manufacture and field of scientific study.Along with developing rapidly of integrated circuit (Integrated circuit) manufacture, biochip technology, high-precision digital control process technology and high-velocity scanning detection etc., the stroke of positioning system, speed, acceleration and precision are had higher requirement, also extremely urgent to the research of high speed, high-accuracy position system.It is high speed, the typical application of high-accuracy position system that IC manufactures, it is the strategic industry of national economy and social development, promoting economic development, social progress, uplift the people's living standard and safeguard national security etc., aspect plays an important role, and has become the focus of current international competition and has weighed the important symbol of a country up-to-dateness and overall national strength.

Yet for ultraprecise axis Nano-positioners, the positioning precision of system and the raising of travelling speed are contradiction.The raising of travelling speed, acceleration, increases the inertial force of mechanism, and the frequency that inertial force changes also strengthens thereupon, system is easy to produce elastic deformation and oscillation phenomenon, both destroy the kinematic accuracy of mechanism, increased the Time Created of mechanically stable, reduced again operation and the positioning precision of system.Hi-Fix wishes that mechanism's operation is mild, and high productivity is wished system high-speed to-and-fro movement high speed start and stop.Meanwhile, in control system, the sensor of feedback position information is also the important step that restriction positioning precision and movement velocity improve.For example as the resolution of the precise grating chi of displacement transducer to nanoscale, but owing to being subject to the restriction of signal deteching circuit sweep frequency, the maximum resolution of translational speed and its measurement that allows of grating scale is inversely proportional to.On the other hand, the large stroke of positioning system and high precision are also conflicting.At present large stroke drives and the precision of the kind of drive (precision lead screw transmission, linear electric motors, voice coil motor etc.) is generally limited in micron order; The positioning precision as driver that the piezoelectric ceramics of take is representative reaches nanoscale, but stroke can only reach tens microns.How well to solve these contradictions, realize large stroke, at a high speed, high-accuracy position system becomes current microelectronics industry circle problem demanding prompt solution.

Summary of the invention

The object of the invention is to overcome the shortcoming of above-mentioned prior art, propose a kind of have large stroke, at a high speed, the axis Nano-positioners of high precision double drive.

For solving the problems of the technologies described above, the invention provides a kind of large travel high-speed double drive axis Nano-positioners, described axis Nano-positioners comprises movement locus order set, main control computer, PMAC motion control board, servo control system, locating platform and Measurement and Control System, wherein said locating platform comprises grand moving platform and micropositioner, by grand moving platform, complete high-speed motion, carry out coarse positioning, solve the speed issue of whole axis Nano-positioners, then by micropositioner, complete accurate Micro-positioning, first this axis Nano-positioners utilizes movement locus order set to carry out trajectory planning to locating platform, recycling movement locus order set is by trajectory planning instruction input main control computer, main control computer sends to PMAC motion control board by PEWIN interface by trajectory planning instruction, PMAC motion control board is controlled locating platform by the parameter of setting and trajectory planning instruction and is realized running fix, while Measurement and Control System is grand moving platform and the micropositioner physical location of detection and location platform constantly, and by detection signal real-time Transmission to PMAC motion control board, PMAC motion control board is through sampling processing, error is calculated and error compensation, Real-time Feedback is to servo control system, thereby guarantee the quick tracking response speed of locating platform and nano level kinematic accuracy.

Locating platform of the present invention comprises: grand moving platform and micropositioner, and wherein, grand moving platform is driven by long stroke linear electric motors, realizes long stroke, high-speed motion, and micropositioner is driven by short stroke planar motor, realizes high precision fine tuning; Long stroke is comprised of X-direction and each permanent-magnetism linear motor of Y-direction, and Y-direction motor stator and X-direction electric mover machinery connect firmly, and adopts linear grid ruler to form close-loop feedback and controls; Short stroke level is controlled by Lorentz lorentz's planar motor to motion, and Lorentz lorentz's motor is comprised of 3 magnetic motors, and its stator coil and Y-direction linear motor rotor machinery connect firmly, and adopts 3 axle laser interferometer to make position probing and forms close-loop feedback control.

Wherein, planar motor is carried out to mobile decoupling, due to when system is located, the position command that main control computer is issued locating platform is precision workpiece stage (x _cG, y _cG, θ _cGz) to desired location, and precision workpiece stage drive motor output be an x to the position of two y to motor, so need first its drive motor to be carried out to coordinate conversion before precision workpiece stage is controlled, with the high efficiency that guarantees to control, thus control accuracy and the response speed of raising system.

The control of locating platform of the present invention takes principal and subordinate to control, short stroke motor is main control object, with laser interferometer measurement, feed back, complete high-precision motion among a small circle, long-range motor as short distance motor from control system, with linear grid ruler, measure feedback, complete long travel high-speed and slightly move.Between length stroke, the relative position of pursuit movement is detected by linear grid ruler, when linear grid ruler detects work stage and moves to target location within setpoint distance, be generally several microns, 1-9 micron for example, stop the motion of long-range motor, be switched to short distance motor movement, until micropositioner reaches target location, and always attempting to keep both relative positions from moving is zero, to guarantee high kinematic accuracy and the quick tracking response speed of following the tracks of.

Wherein, laser interferometer adopts three-axis measurement system, can be to the x of micropositioner, y ₁, y ₂carry out precision measurement; Linear grid ruler can carry out precision measurement to the X of coarse motion platform, Y-direction, forms close-loop feedback; This axis Nano-positioners has been considered three-axis measurement and the control of three axles when design, can be to x, y ₁, y ₂control, to overcome locating platform, rock the error causing.

Principle of the present invention is:

Large stroke, at a high speed, the grand micro-Dual Drive axis Nano-positioners of high precision, it comprises movement locus order set, main control computer, PMAC motion control board, servo control system, locating platform (grand moving platform and micropositioner) and Measurement and Control System.This axis Nano-positioners has been considered three-axis measurement and the control of three axles when design, can be to x, y ₁, y ₂control, to overcome locating platform, rock the error causing.In physical construction, adopt grand moving platform to add the unitized construction of micropositioner, by grand moving platform, completed high-speed motion, carried out coarse positioning, solved the speed issue of whole system; Then by micropositioner, complete accurate location, so both can make positioning system reach high positioning precision and response speed, and control reliable.Concrete operations flow process is: first positioning system carries out trajectory planning by trajectory planning instruction input main control computer to locating platform, main control computer sends to PMAC Control card by PEWIN interface by trajectory planning instruction, PMAC Control card is controlled locating platform by the parameter of setting and trajectory planning instruction and is realized running fix, while measuring system is the physical location of detection and location platform constantly, and by detection signal real-time Transmission to PMAC control card, PMAC control card is through sampling processing, error is calculated, error compensation, Real-time Feedback is to servo-control system, thereby guarantee the flat quick tracking response speed in location and nano level kinematic accuracy.Measuring system of the present invention comprises: laser interferometer, linear grid ruler, displacement transducer, speed pickup etc.Wherein laser interferometer adopts three-axis measurement system, can be to the x of micropositioner, y ₁, y ₂carry out precision measurement; Linear grid ruler can carry out precision measurement to the X of coarse motion platform, Y-direction, forms close-loop feedback; Speed pickup can carry out precision measurement to the speed of locating platform, realizes speed feedback.

The present invention's advantage is compared with prior art:

The present invention adopts long stroke linear electric motors micron order coarse motion to add short stroke Lorentz lorentz motor nanoscale fine tuning structure, by introducing, take PMAC motion control card that high performance DSP is core and planar motor is carried out to mobile decoupling, can carry out high speed, the control of high real-time multiaxis to positioning system, thereby effectively improve response speed and the positioning precision of positioning system.

Accompanying drawing explanation

Fig. 1 is the basic schematic diagram of the present invention;

Fig. 2 is three-axis measurement system schematic;

Fig. 3 is servo-control system multiloop control block diagram schematic diagram;

Fig. 4 is position coordinates decoupling zero schematic diagram;

Fig. 5 (a), Fig. 5 (b) are position coordinates decoupling zero step schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, structural principle of the present invention and principle of work are described in further detail.

Fig. 1 is basic side schematic diagram of the present invention, as shown in Figure 1, a kind of large travel high-speed double drive axis Nano-positioners mainly comprises movement locus order set 101, main control computer 102, PMAC motion control board 103, servo control system 104, locating platform and Measurement and Control System 107.Locating platform comprises grand moving platform 105 and micropositioner 106.First by movement locus order set 101, the movement locus of locating platform (grand moving platform 105 and micropositioner 106) is offered to main control computer 102, main control computer 102 sends to PMAC motion control board 103 by PEWIN interface by trajectory planning instruction, grand moving platform 105 and micropositioner 106 that PMAC motion control board 103 is controlled in locating platform by the parameter of setting and trajectory planning instruction are realized precise motion and location, simultaneously Measurement and Control System 107 constantly detection and location platform in grand moving platform 105 and micropositioner 106 physical locations, and by detection signal real-time Transmission to PMAC motion control board 103, PMAC motion control board 103 is through sampling processing, error is calculated, error compensation, Real-time Feedback is to servo control system 104, thereby guarantee the flat quick tracking response speed in location and nano level kinematic accuracy.

Be illustrated in figure 2 laser interferometer three-axis measurement system, this axis Nano-positioners has been considered three-axis measurement and the control of three axles when design, can be to the x of micropositioner (106), y ₁, y ₂direction is accurately controlled.

Be illustrated in figure 3 servo-control system multiloop control block diagram, this block diagram mainly comprises position command 301, position ring controller 302, speed ring controller 303, pwm power amplifier 304, drive motor 305, locating platform 306, position feed-forward controller 307, current feedback 308, speed feedback 309, position feedback 310.This servo-drive system multiloop control block diagram is that three traditional rings are controlled, and position ring, speed ring and acceleration ring, belong to prior art.Because worktable should have higher positioning precision and kinematic accuracy, have again very high velocity and acceleration, and increased acceleration easily causes vibration.And in order to guarantee the operation of locating platform high precision, the support of worktable generally adopts balanced type air floatation component, and air supporting support component easily causes low-frequency oscillation.Based on above reason, worktable adopts three traditional ring control strategies, and position ring, speed ring and acceleration ring, make system both can suppress vibration, has again good tracking characteristics.During three rings are controlled, position transducer adopts two-frequency laser interferometer, and speed and acceleration feedback in speed ring, acceleration ring can be used speed pickup, acceleration transducer, also can estimate by the displacement detecting.In addition, also introduce position feed-forward compensator and compensate the error causing because of damping and inertia, and adopt on this basis filtering technique further to suppress the mechanical resonant of system.

As shown in Figure 4,5, due to when positioning system is worked, the position command that main control computer is issued locating platform is x, y, the θ of micropositioner _zto desired location, and micropositioner drive motor output be an x to the position of two y to motor, so need first its drive motor to be carried out to position coordinates conversion before micropositioner is controlled, position coordinates conversion refers to the location of instruction (x of input _cG, y _cG, θ _cGz) carry out coordinate conversion, be transformed into direct position input (x, the y of three motors ₁, y ₂).

As shown in Figure 4, S1 is y ₁motor center of gravity and micropositioner barycenter are in the distance of x axle, and S2 is y ₂motor center of gravity and micropositioner barycenter be in the distance of x axle, S3 be x motor center of gravity and micropositioner barycenter in the distance of y axle, S1, S2 and S3 are constant.

As shown in Figure 5, in order to obtain the location of instruction (x of input _cG, y _cG, θ _cGz) and motor input position (x, y ₁, y ₂) between relation, position command can be completed in two steps, first micropositioner centroid position is moved to the location of instruction (x _cG, y _cG) locate, then micropositioner is rotated to θ around z axle _cGz.

Micropositioner centroid position moves to the location of instruction (x _cG, y _cG) while locating, now motor position (x ', y ₁', y ₂') and instruction position (x _cG, y _cG, θ _cGz) pass be:

$\left\{\begin{array}{c}{x}^{\′}=x_{\mathrm{CG}}\\ {y_1}^{\′}=y_{\mathrm{CG}}\\ {y_2}^{\′}=y_{\mathrm{CG}}\end{array}\right.$

Micropositioner is rotated to θ _cGzafter, the position of x motor is:

x＝x′-S3*sinθ _CGz

Due to y ₁, y ₂motor is symmetrical about x motor, so y ₁, y ₂the position of motor is:

$\left\{\begin{array}{c}{y}_1={y_1}^{\′}-S3*(1-\cos {\mathrm{\θ}}_{\mathrm{CGz}})+S1*\sin {\mathrm{\θ}}_{\mathrm{CGz}}\\ y_2={y_2}^{\′}-S3*(1-\cos {\mathrm{\θ}}_{\mathrm{CGz}})-S2*\sin {\mathrm{\θ}}_{\mathrm{CGz}}\end{array}\right.$

Comprehensive above formula can obtain,

$\left\{\begin{array}{c}x=x_{\mathrm{CG}}-S3*\sin {\mathrm{\θ}}_{\mathrm{CGz}}\\ y_1=y_{\mathrm{CG}}-S3*(1-\cos {\mathrm{\θ}}_{\mathrm{CGz}})+S1*\sin \\ y_2=y_{\mathrm{CG}}-S3*(1-\cos {\mathrm{\θ}}_{\mathrm{CGz}})-S2*\sin {\mathrm{\θ}}_{\mathrm{CGz}}\end{array},{\mathrm{\θ}}_{\mathrm{CGz}}\right.$

Above formula conversion can obtain,

$\left\{\begin{array}{c}{x}_{\mathrm{CG}}=x-\frac{S3}{S1+S2}(y_1-y_2)\\ y_{\mathrm{CG}}=\frac{1}{S1+S2}(S1*y_2+S2*y_1)+S3*(1-\cos {\mathrm{\θ}}_z)\\ {\mathrm{\θ}}_{\mathrm{CGz}}=\arcsin \frac{y_1-y_2}{S1+S2}\end{array}\right.$

Work as θ _cGzwhen very little, motor position (x, y ₁, y ₂) and instruction position (x _cG, y _cG, θ _cGz) relation, forward position coordinate conversion expression formula is:

$\left[\begin{array}{c}x\\ y_1\\ y_2\end{array}\right]=\left[\begin{array}{ccc}1& 0& -S3\\ 0& 1& S1\\ 0& 1& -S2\end{array}\right]\left[\begin{array}{c}{x}_{\mathrm{CG}}\\ y_{\mathrm{CG}}\\ {\mathrm{\θ}}_{\mathrm{CGz}}\end{array}\right]$

By above formula, converted, the reverse position coordinates converting expressing formula that can obtain drive motor is:

$\left[\begin{array}{c}{x}_{\mathrm{CG}}\\ y_{\mathrm{CG}}\\ {\mathrm{\θ}}_{\mathrm{CGz}}\end{array}\right]=\left[\begin{array}{ccc}1& \frac{S3}{S1+S2}& -\frac{S3}{S1+S2}\\ 0& \frac{S2}{S1+S2}& \frac{S1}{S1+S2}\\ 0& \frac{1}{S1+S2}& -\frac{S1}{S1+S2}\end{array}\right]\left[\begin{array}{c}x\\ y_1\\ y_2\end{array}\right]$

In sum, a kind of large travel high-speed double drive axis Nano-positioners of the present invention, by introducing, take PMAC Control card that high performance DSP is core and positioning system is carried out to multiaxis control in real time, greatly to have improved response speed and the real-time of positioning system; Servo control loop takes many loop feedback to control, and makes system both can suppress vibration, has again good tracking characteristics, and adopts on this basis filtering technique further to suppress the mechanical resonant of system, has reduced control difficulty; By micropositioner being carried out to simple position coordinates decoupling zero, the high efficiency that the system that guaranteed is controlled, thereby control accuracy and the response speed of raising system.

Claims (1)

1. a large travel high-speed double drive axis Nano-positioners, it is characterized in that: described axis Nano-positioners comprises movement locus order set (101), main control computer (102), PMAC motion control board (103), servo control system (104), locating platform and Measurement and Control System (107), wherein said locating platform comprises grand moving platform (105) and micropositioner (106), by grand moving platform, complete high-speed motion, carry out coarse positioning, solve the speed issue of whole axis Nano-positioners, then by micropositioner, complete accurate Micro-positioning, first this axis Nano-positioners utilizes movement locus order set (101) to carry out trajectory planning to locating platform, recycling movement locus order set (101) is by trajectory planning instruction input main control computer (102), main control computer (102) sends to PMAC motion control board (103) by PEWIN interface by trajectory planning instruction, PMAC motion control board (103) is controlled locating platform by the parameter of setting and trajectory planning instruction and is realized running fix, while Measurement and Control System (107) is grand moving platform (105) and micropositioner (106) physical location of detection and location platform constantly, and by detection signal real-time Transmission to PMAC motion control board (103), PMAC motion control board (103) is through sampling processing, error is calculated and error compensation, Real-time Feedback is to servo control system (104), thereby guarantee the quick tracking response speed of locating platform and nano level kinematic accuracy,

Control to locating platform is specially: grand moving platform is driven by long stroke linear electric motors, realizes long stroke, high-speed motion, and micropositioner is driven by short stroke planar motor, realizes high precision fine tuning; Long stroke is comprised of X-direction and each permanent-magnetism linear motor of Y-direction, and Y-direction motor stator and X-direction electric mover machinery connect firmly, and adopts linear grid ruler to form close-loop feedback and controls; Short stroke level is controlled by Lorentz lorentz's planar motor to motion, and Lorentz lorentz's motor is comprised of 3 magnetic motors, and its stator coil and Y-direction linear motor rotor machinery connect firmly, and adopts 3 axle laser interferometer to make position probing and forms close-loop feedback control;

When planar motor is driven, planar motor is carried out to mobile decoupling, due to when system is located, the position command that main control computer is issued locating platform is micropositioner (x _cG, y _cG, θ _cGz) to desired location, and micropositioner drive motor output be an x to the position of two y to motor, so before being controlled, micropositioner needs first its drive motor to be carried out to coordinate conversion, with the high efficiency that guarantees to control, thus control accuracy and the response speed of raising system;

The control of described locating platform takes principal and subordinate to control, and short stroke motor is main control object, with laser interferometer measurement, feeds back, complete high-precision motion among a small circle, long-range motor as short distance motor from control system, with linear grid ruler, measure feedback, complete long travel high-speed and slightly move; Between length stroke, the relative position of pursuit movement is detected by linear grid ruler, when detecting work stage, linear grid ruler moves to target location when setpoint distance is several microns, stop the motion of long-range motor, be switched to short distance motor movement, until micropositioner reaches target location, and always attempting to keep both relative positions from moving is zero, to guarantee high kinematic accuracy and the quick tracking response speed of following the tracks of;

This positioning system is in order to obtain the location of instruction (x of input _cG, y _cG, θ _cGz) and motor input position (x, y ₁, y ₂) between relation, position command can be completed in two steps, first micropositioner centroid position is moved to the location of instruction (x _cG, y _cG) locate, then micropositioner is rotated to θ around z axle _cGz;

Micropositioner centroid position moves to the location of instruction (x _cG, y _cG) while locating, now motor position (x ', y ₁', y ₂') and instruction position (x _cG, y _cG, θ _cGz) pass be:

$\left\{\begin{array}{c}{x}^{\′}=x_{\mathrm{CG}}\\ {y_1}^{\′}=y_{\mathrm{CG}}\\ {y_2}^{\′}=y_{\mathrm{CG}}\end{array}\right.$

S1 is y ₁motor center of gravity and micropositioner barycenter are in the distance of x axle, and S2 is y ₂motor center of gravity and micropositioner barycenter be in the distance of x axle, S3 be x motor center of gravity and micropositioner barycenter in the distance of y axle, S1, S2 and S3 are constant;

Micropositioner is rotated to θ _cGzafter, the position of x motor is:

x＝x′-S3*sinθ _CGz

Due to y ₁, y ₂motor is symmetrical about x motor, so y ₁, y ₂the position of motor is:

$\left\{\begin{array}{c}{y}_1={y_1}^{\′}-S3*(1-\cos {\mathrm{\θ}}_{\mathrm{CGz}})+S1*\sin {\mathrm{\θ}}_{\mathrm{CGz}}\\ y_2={y_2}^{\′}-S3*(1-\cos {\mathrm{\θ}}_{\mathrm{CGz}})-S2*\sin {\mathrm{\θ}}_{\mathrm{CGz}}\end{array}\right.$

Comprehensive above formula can obtain,

$\left\{\begin{array}{c}x=x_{\mathrm{GC}}-S3*\sin {\mathrm{\θ}}_{\mathrm{CGz}}\\ y_1=y_{\mathrm{CG}}-S3*(1-\cos {\mathrm{\θ}}_{\mathrm{CGz}})+S1*\sin \\ y_2=y_{\mathrm{CG}}-S3*(1-\cos {\mathrm{\θ}}_{\mathrm{CGz}})-S2*\sin {\mathrm{\θ}}_{\mathrm{CGz}}\end{array},{\mathrm{\θ}}_{\mathrm{CGz}}\right.$

Above formula conversion can obtain,

$\left\{\begin{array}{c}{x}_{\mathrm{CG}}=x-\frac{S3}{S1+S2}(y_1-y_2)\\ y_{\mathrm{CG}}=\frac{1}{S1+S2}(S1*y_2+S2*y_1)+S3*(1-\cos {\mathrm{\θ}}_z)\\ {\mathrm{\θ}}_{\mathrm{CGz}}=\arcsin \frac{y_1-y_2}{S1+S2}\end{array}\right.$

Work as θ _cGzwhen very little, motor position (x, y ₁, y ₂) and instruction position (x _cG, y _cG, θ _cGz) relation, forward position coordinate conversion expression formula is:

$\left[\begin{array}{c}x\\ y_1\\ y_2\end{array}\right]=\left[\begin{array}{ccc}1& 0& -S3\\ 0& 1& S1\\ 0& 1& -S2\end{array}\right]\left[\begin{array}{c}{x}_{\mathrm{CG}}\\ y_{\mathrm{CG}}\\ {\mathrm{\θ}}_{\mathrm{CGz}}\end{array}\right]$

By above formula, converted, the reverse position coordinates converting expressing formula that can obtain drive motor is:

$\left[\begin{array}{c}{x}_{\mathrm{CG}}\\ y_{\mathrm{CG}}\\ {\mathrm{\θ}}_{\mathrm{CGz}}\end{array}\right]=\left[\begin{array}{ccc}1& \frac{S3}{S1+S2}& -\frac{S3}{S1+S2}\\ 0& \frac{S2}{S1+S2}& \frac{S1}{S1+S2}\\ 0& \frac{1}{S1+S2}& -\frac{S1}{S1+S2}\end{array}\right]\left[\begin{array}{c}x\\ y_1\\ y_2\end{array}\right].$