A micro-motion stage used in a photolithography motion stage system and its control method

Abstract

The invention relates to a micro-motion platform for a photo-etching motion platform system and a control method thereof. The micro-motion platform is mounted on a motion part of a workpiece platformand comprises a micro-motion plate and four vertical motors arranged at the bottom of the micro-motion plate; the four vertical motors are arranged at two sides of the micro-motion plate; each vertical motor is correspondingly provided with a sensor; an Rz motor is arranged between the two vertical motors at the same side; an air-floating decoupling device is arranged at a part which is no more than 30mm far away from the mass center of the micro-motion plate. According to the micro-motion platform provided by the invention, the four vertical motors and the four sensors are adopted to realizeredundancy control according to a redundancy driving principle and a redundancy measurement principle and the requirements on the frequency of the micro-motion plate are reduced; only if the frequencyof the micro-motion plate reaches about 120Hz, the bandwidth of 50Hz can be obtained; the requirements on valuable materials are reduced and the cost is reduced; the air-floating decoupling device isclose to the mass center of the micro-motion plate, but not the form center of the micro-motion plate, so that the output power of the Rz motor is extremely reduced.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a micro-moving stage used in a lithography moving stage system and a control method thereof. Background technique [0002] The sixth-generation step-scan projection lithography machine (hereinafter referred to as 6G) is a special equipment for making TFT (Thin Film Transistor, English full name: Thin Film Transistor) circuits for flat panel display devices. It is compatible with the 5.5th generation step-scan projection lithography machine (1500×1300mm) size substrate. The imaging resolution of the step-scan projection lithography machine is 1.7um (based on GHI Line) / 1.5um (based on I Line, optional), the overlay accuracy is 0.5um, and the CDU index is 7%@BF, BE, 10%@ TF, BE, focal depth 8um (based on GHI Line) / 6um (based on I Line, optional), scanning speed 0.8m / s, compared with the 4.5th generation step-scan projection lithography machine (hereinafter referred to as 4.5G), The 6...

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Problems solved by technology

Due to the larger size of the 6G workpiece table, the requirements for the micro-motion table are also higher, so the original design for 4.5G is no longer suitable for 6G

[0004] like figure 1 As shown, the existing micro-motion table structure proposed for 4.5G includes a micro-motion plate 1, three vertical motors 2 and three gravity compensators 3 are respectively arranged under the micro-motion plate 1, and two oppositely arranged The Rz motor 4 is used to drive the movement of the micro-motion plate 1 in the Z direction and the Rz direction. This structure restricts the control bandwidth of the Z direction due to the first-order structural modal frequency of the micro-motion plate 1. For example, to achieve a control bandwidth of 50 Hz, the micro The frequency of the moving plate 1 must reach 150 Hz, and it is inevitable to use materials such as ceramics to achieve greater rigidity in the design of parts, which is not economical; in the prior art, ring air bearings 5 ​​and hinged air bearings 6 are used to decouple Rx and Ry Directional torque, such as figure 2 As shown, when the hinged air bearing 6 generates torque in the Rx and Ry directions, the air film thickness L will change. If the torque is too large, the air film thickness L will be too small, which will affect the air bearing function and the torsional stroke will be insufficient. ; Additionally, if image 3 As shown, the center of the existing ring air bearing 5 coincides with the centroid of the micro-movement plate 1, the eccentric moment is relatively large, it is difficult to control, and two Rz motors 4 are required to generate a large thrust (respectively F Rz1 and F Rz2 ), used to balance the inertial force generated by the horizontal acceleration

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