Movement And Measurement Systems Decoupling Algorithm For Wafer Stage And Reticle Stage

Lithography, as important production tools of large scale integrated circuitsmanufacturing, is increasingly becoming an important indicator for measuring acountry’s high-tech development. Wafer Stage and Reticle Stage, as one of theimportant parts of the lithography, its development and research has became thecore of the lithography machine production. It can be said that the technologicallevel of the Wafer Stage and Reticle Stage has a direct impact on lithographyequipment capacity.The high speed and accuracy requirements of the Wafer Stage and ReticleStage become difficult to control. The Short Stage of Wafer Stage is controlledby six voice coil motor as well as Reticle Stage. Six motor coordinate each otherto achieve the movement in six degree of freedom. In order to control the motionof the Wafer Stage and Reticle Stage in high speed and accuracy, we need todecouple the six motor accurately, and to analyze the assemble inaccuracy.First of all, the article gives a brief introduction for the working principle ofthe Wafer Stage and Reticle Stage. Then, the article establishes a model of theShort Stage of the Wafer Stage and Reticle Stage. By means of analyzing theforce and torque of the six motor to the Short Stage, the article explain therelationship between the six degrees of freedom and the force and torque of thesix motor. So as to control the motion of the Wafer Stage and Reticle Stage in sixdegrees of freedom in high speed and accuracy, the article makes use ofmathematical software to calculate the inverse transformation matrix. Write aVC++visualization program, easy to solve the influence of the motor forcechange with assemble inaccuracy.It is easy to produce assemble inaccuracy in electrical installation and stagemachine. While assemble inaccuracy could make error when the Wafer Stage orReticle Stage is moving. Therefore, it is essential to add the assemble inaccuracyto the transformation. By ways of comparing the expended movement trendswith the actual movement trends, we also can get the coordinate of the center ofgravity of the Short Stage.At last, the article researches the measurement of the Wafer Stage or ReticleStage. The article plans the measurement, and decouples the measurement data from the laser interferometer and the capacitance sensor. The decoupledmeasurement data can be used as the motive data of the Short Stage of the WaferStage and Reticle Stage in six degree of freedom, to achieve the closed loop ofthe entire system.