A Two-Dimensional Self-Calibration Marker Detection and Alignment System

Abstract

A two-dimensional self-calibration mark point detection and alignment system, including a zero signal reader, a two-dimensional workbench, a grating ruler auxiliary calibration plate, a reading head detection part, and a measurement reference frame; the grating ruler auxiliary calibration plate includes X, Y The direction of the grating ruler with a zero mark point; the detection part of the reading head includes the grating ruler reading head and the mounting bracket; the alignment system is based on the grating ruler detection alignment principle and the zero signal detection principle to achieve mark point alignment. The reading head detects the signal of the zero mark point on the auxiliary calibration board of the grating ruler and transmits the signal to the zero signal reader. At the same time, the two-dimensional workbench records its own position coordinates and transmits the signal to the zero signal reader to obtain The position coordinates of the zero mark point. The alignment system can be used in two-dimensional self-calibration technology to achieve nanoscale resolution and alignment accuracy; the signal readout delay is small, and can be applied to dynamic and high-speed calibration of the workbench; the overall structure is relatively simple, and the price is high. Context insensitive.

Description

technical field [0001] The invention relates to a detection and alignment system, in particular to a two-dimensional self-calibration mark point detection and alignment system. Background technique [0002] The application of ultra-precision worktables in the field of precision engineering is becoming more and more extensive, and the measurement accuracy requirements for multi-dimensional workbenches are also getting higher and higher. In the field of ultra-precision processing (such as high-end lithography machines), the multi-dimensional measurement accuracy often needs to reach nanometers level or even sub-nanometer level. The development of self-calibration technology has brought new solutions to the calibration problems of ultra-precision workbench measurement systems. Among them, the self-calibration method is based on the use of an auxiliary measuring device whose accuracy of the marking point is lower than that of the object being calibrated as a medium. Through the...

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Problems solved by technology

However, there are obvious disadvantages and shortcomings in this scheme. Due to the limitation of the optical diffraction limit, the highest alignment accuracy is only about 100nm, which greatly affects the final self-calibration effect; secondly, due to the use of optical The microscope cooperates with the image sensor as a detection system, which involves a large number of image data processing problems, resulting in a low frequency of signal acquisition. In this case, only static alignment can be performed, and it is difficult to align and calibrate during the movement of the workbench. This largely leads to long self-calibration process and low efficiency; moreover, due to the use of optical microscopes and image sensors and other equipment, it is bound to bring about high cost and high system complexity; and this scheme will be subject to certain Environmental impact, so the requirements for the working environment are relatively high

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