SU470793A1 - Two-coordinate positioning system - Google Patents

Description

one

The invention relates to the field of equipment for the production of microelectronic products, in particular, to devices for the production and control of photo masks.

Two-coordinate positioning systems are known, comprising a program input unit, connected to a control unit connected to coordinate actuators, and displacement sensors connected to converters in each coordinate.

The disadvantage of these schemes is that the positioning accuracy is limited by uncontrollable faults in the direction and direction.

The aim of the invention is to improve the accuracy of the performance of the pos-ion-ionization system.

The goal is achieved by introducing a serially connected correction sensor, pulse generator, reversible counter, phase shifter and phase detector into the positioning system for each coordinate. The outputs of all phase detectors are connected to the inputs of the control unit, and the transducer outputs of each coordinate are connected to the inputs of the phase shifter and phase detector of the same coordinate. The output of the correction sensor for each coordinate is connected to one of the INPUTS of the pulse formers of the other coordinate.

Pa fit. I presents the structural scheme of the positioning system; in fig. 2 - dependences of the values of positioning errors on the displacements along the X and / Y coordinates.

The two-coordinate positioning system contains a program input unit 1 connected to control unit 2, which in turn is connected to coordinate actuators 3 and 4, displacement sensors 5 and 6, connected by outputs to converters 7 and 8, respectively, controlled phase shifters 9 and 10, reversible counters 11 and 12, pulse shapers 13 and 14, correction sensors 15 and 16, and phase detectors 17 and 18.

The error signals from the program block 1 or phase detectors 17 and 18 are converted by the control unit 2 into a deceleration or movement command of the actuators 3 and 4. The displacement sensor, such as the displacement sensor 5, converts the mechanical movement of the coordinate table into periodic electrical signals that are known methods are converted by the Converter 7 into a phase-modulated carrier frequency signal generated by the generator included in the converter 7. The phase detector 17 is generated Displays motion information by measuring the phase of the output signal of the converter 7 relative to the reference signal supplied to the phase detector 17 from the output of the controlled phase shifter 9. The quality of the input signal fed to the signal input of the phase shifter 0 uses the signal of the carrier frequency of the converter 7. On the control input of the phase shifter 9 receives signals from the indicator outputs of the reversible counter 11. Changing the state of the reversing counter 11 per unit of the youngest. causes a change in the phase AF of the output signal relative to the phase of the signal on the input of the phase shifter 9 by the value of

L :: 2r.lN,

where / V - counter conversion factor 11.

A movement sensor 6, a converter 8, a phase shifter 10, a reversible counter 12, and a phase detector 18 are similarly constructed and operate.

The principle of increasing the accuracy of the two-coordinate positioning system is as follows.

Due to the manufacturing faults of the guides, the displacement of the coordinate table along the X axis causes its displacement along the Y axis, with each value of X coordinate corresponding to a certain displacement magnitude of the software along the Y axis (curve 19 in Fig. 2). In addition, the testing of the Y coordinate, carried out on a displacement transducer, for example displacement transducer 5, occurs with an error boog, (curve 20 in FIG. 2), which is the error of displacement transducer 5. Thus, the total positioning error of bu coordinate is equal to

S-V + V

Fault compensation 6 is performed as follows.

The incapacities of the bougain “are quantum in level Ae:

Ae g s / L,

where e is the period of the measure of the displacement sensor 5;

N-conversion factor of the reversible counter 11.

Coordinates 19 and 20 determine the coordinates () and (xi-Xit), in which a correction must be entered into the results of the reference movement along the coordinate Y by the phase detector 17. In this case, the sign of the correction is also determined. Correction signals are generated by corresponding correction sensors 16 and 15, mechanically or informationally connected to the coordinate tables of the positioning system. In this case, the correction sensor 15 generates signals, correcting the error, and the correction sensor 16 - signals, correcting the error

inc- At the position of the coordinate table and points (1-ut), correction signals are generated by the iO correction sensor, and at points (x.i-x,) signals of correction sensors 1b are formed.

The signals from the outputs of the sensors -correction io and ib are sent to the inputs of the pulse shaper 1.3 .and then to the inputs of the reversive counter I.

With the arrival of each pulse, a change in the state of the counter 11 or -1 occurs, which causes a change in the phase of the output signal of the phase shifter Y by an amount, and this change in phase

queue, causes a change in the result of the reference movement of the phase detector 18 by the value

As a result, the positioning error of the Y coordinate, caused by the displacement of the displacement sensor 5 and the errors of the guides of the coordinate table, does not exceed ± Ae.

Similarly, the correction of positioning errors is carried out along the X coordinate.

Thus, the correction sensor 15 generates signals that correct the errors of the displacement sensor 5, the coordinates Y, and the signals correct the errors of the directional coordinates X. These signals are fed to the inputs of the pulse formers 13 and 14, respectively. Similarly, the correction sensor 16 generates the signals correcting the errors of the displacement sensor 6 are the coordinates of X, and the signals correcting the faults of the guiding coordinates | Y, which are fed respectively to the inputs of the pulse shapers 14 and 13.

Subject invention

A two-coordinate positioning system, comprising a program input unit, connected to a control unit connected to coordinate actuators, and displacement sensors connected to the transducers in each coordinate, which is

accuracy of the system, serially connected correction sensor, pulse driver, reversible counter, phase shifter and phase detector, the outputs of all phase detectors are connected to the inputs of the control unit, and the transducer outputs of each coordinate are connected to the inputs of the phase shifter and the phase detector of the same coordinates, with the output of the correction sensor for each coordinate connected to one of the inputs of the pulse former of the other coordinate.

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