Measurement method and system for center-of-gravity position

Abstract

The invention belongs to the technical field of ultra-precision active vibration reduction and discloses a measurement method for center-of-gravity position. The method is realized by a center-of-gravity measuring system. The center-of-gravity measuring system comprises a controller and more than two active shock absorbers, each active shock absorber cooperates with an actuator and a sensor, the active shock absorber is used for supporting a load, and a support point is formed at each active shock absorber. The measuring method comprises the following steps: S1, starting the center-of-gravitymeasuring system, the controller adjusting the output amplitude of each actuator, so that the load only has a response in the gravity direction; and S2, calculating according to the output amplitude of each actuator and the distance between adjacent support points to obtain the center-of-gravity position of the load. The invention further discloses a corresponding measurement system. According tothe measurement method, rapid identification of the center of gravity of the load of the precise active shock absorber is realized, without the help of extra sensors, the influence of the process on equipment is small, and the measuring precision is high.

Description

technical field [0001] The invention belongs to the technical field of precision vibration reduction, and more specifically relates to a method and system for measuring the position of the center of gravity. The measuring method can be used in photolithography machines, scanning electron microscopes, precision processing equipment, precision instruments, optical experiment equipment, precision medical equipment, etc. Measurement of the center of gravity of precision machining equipment. Background technique [0002] With the development of science and technology, the application of ultra-precision equipment represented by photolithography machines and scanning electron microscopes is becoming more and more extensive, and the accuracy of its manufacturing and measurement is getting closer and closer to the physical limit. In the process of micro / nano processing or measurement, environmental vibration has become a bottleneck problem restricting its accuracy. Precision process...

AI Technical Summary

Problems solved by technology

Due to the complex structure of precision equipment and equipment and moving parts, it is difficult to determine the position of the center of gravity by theoretical calculation, and it is necessary to conduct on-site inspection through certain methods

[0003] The existing center of gravity measurement schemes generally use methods such as hoisting experiments or force sensors, but such methods are not suitable for occasions where the equipment is inconvenient to move or the system is inconvenient to install additional force sensors, especially not suitable for equipment such as photolithography machines and scanning electron microscopes. For precision equipment or instruments that are convenient for large-scale movement, the active shock absorber of its supporting parts is not convenient for installing additional force sensors

Secondly, in the process of measuring the center of gravity of some precision equipment, the position of the center of gravity of the load changes at any time. For example, during the working process of the lithography machine, the mask table and the silicon wafer move in the opposite direction along the Y direction at a certain speed ratio, and the load is completed. After one exposure, the wafer stage moves to the next field along the X direction and continues to expose. The traditional center of gravity measurement method is difficult to adapt to the center of gravity measurement of this dynamically changing load.

In addition, traditional methods such as hoisting experiments or force sensors, especially hoisting experiments, cannot measure the accuracy of the center of gravity to meet the accuracy requirements of precision instruments or equipment.

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