Position measuring device of motion platform and measuring method of position measuring device

Abstract

The invention discloses a position measuring device of a motion platform, which comprises a first stroke interferometer and a first stroke reflecting mirror as well as a second stroke interferometer and a second stroke reflecting mirror, wherein the first stroke interferometer and the first stroke reflecting mirror are used for measuring position information of the motion platform along a first stroke direction, the second stroke interferometer and the second stroke reflecting mirror are used for measuring position information of the motion platform along a second stroke direction, when the motion platform moves along the first stroke, the second stroke reflecting mirror moves in the opposite direction of the first stroke direction of the motion platform, when the motion platform moves along the second stroke, the first stroke reflecting mirror moves in the opposite direction of the second stroke direction of the motion platform, and the invention also discloses a position measuring method adopting the position measuring device of the motion platform. The position of the motion platform can be measured only by the short reflecting mirror, the weakness that the flatness of the surface is not easy to guarantee and the surface is easy to bend and deform because of over-length of the reflecting mirror can be avoided, and the measuring precision can be improved.

Description

technical field [0001] The invention relates to a measuring device, in particular to a position measuring device of a moving platform and a measuring method thereof. Background technique [0002] In a high-precision motion platform control system (such as the workpiece table mask sub-system of a lithography machine), a high-precision measurement system is required, and the measurement device generally uses an interferometer. [0003] See figure 1 and figure 2 , the existing interferometer measuring device comprises a first travel interferometer 12 (i.e. an X direction interferometer) and a first travel mirror 4 for measuring the position of the moving platform 11 along the first travel direction (i.e. the X direction), And the second travel interferometer 13 (ie, the Y direction interferometer) and the second travel mirror 5 for measuring the position of the moving platform 11 after moving along the second travel direction (ie, the Y direction). The first stroke mirror 4...

AI Technical Summary

Problems solved by technology

And the longer the reflector is, the more difficult it is to ensure the flatness of its surface, and it is easy to produce bending deformation

[0005] 2. The beam emitted by the interferometer must be completely perpendicular to the surface of the corresponding mirror. At present, it is realized by adjusting the direction of the beam emitted by the interferometer, and the error is relatively large; it is realized by software, and the algorithm is very complicated.

However, as the length of the reflector increases, the flatness of the reflector becomes more difficult to ensure. In addition, the patent does not explain how to ensure the perpendicularity between the beam and the reflector.

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