US 12,169,367 B2
Vertical motion protection method and device based on dual-stage motion system of photolithography machine
Kaiming Yang, Beijing (CN); Rong Cheng, Beijing (CN); Yu Zhu, Beijing (CN); Ming Zhang, Beijing (CN); Sheng Lei, Beijing (CN); Tao Liu, Beijing (CN); Sen Lu, Beijing (CN); and Xin Li, Beijing (CN)
Assigned to TSINGHUA UNIVERSITY, Beijing (CN)
Appl. No. 18/042,991
Filed by TSINGHUA UNIVERSITY, Beijing (CN)
PCT Filed Mar. 4, 2021, PCT No. PCT/CN2021/079105
§ 371(c)(1), (2) Date Feb. 24, 2023,
PCT Pub. No. WO2022/041673, PCT Pub. Date Mar. 3, 2022.
Claims priority of application No. 202010870392.2 (CN), filed on Aug. 26, 2020.
Prior Publication US 2023/0359132 A1, Nov. 9, 2023
Int. Cl. G03F 7/00 (2006.01)
CPC G03F 7/70725 (2013.01) 10 Claims
OG exemplary drawing
 
1. A vertical motion protection method based on a dual-stage motion system of a photolithography machine, wherein the dual-stage motion system comprises a macro-motion stage and a micro-motion stage located above the macro-motion stage, the macro-motion stage and the micro-motion stage have flat square shapes, and the vertical motion protection method comprises:
establishing a space rectangular coordinate system O-XYZ by taking a point on an upper surface of the micro-motion stage at an initial position as an original point O, wherein an X-axis and a Y-axis are in horizontal directions, and a Z-axis is upward in a vertical direction, the micro-motion stage has three degrees of freedom in directions of the X-axis, the Y-axis and the Z-axis, wherein vertical displacement sensors are respectively disposed at four corners of a lower surface of the macro-motion stage, and the vertical displacement sensors are configured to measure vertical distances between a lower surface of the micro-motion stage and the macro-motion stage respectively, wherein a horizontal displacement measuring device is further provided for measuring displacements of the micro-motion stage in the directions of the X-axis and the Y-axis;
obtaining coordinates of measured points respectively according to data of the vertical displacement sensor and the horizontal displacement measuring device;
obtaining a point normal form equation f(X, Y, Z)=0 of the lower surface of the micro-motion stage in the space rectangular coordinate system O-XYZ by using the coordinates of the measured points;
taking a nearest corner point of a measured point corresponding to a maximum value hmax among measured values of the measured points as a highest point on the lower surface of the micro-motion stage, and obtaining a Z-axis coordinate hb of the highest point on the lower surface of the micro-motion stage at the current time by using the point normal form equation f(X, Y, Z)=0; and
obtaining a Z-axis coordinate hu of a highest point on the upper surface of the micro-motion stage according to the Z-axis coordinate hb of the highest point on the lower surface of the micro-motion stage, and comparing the hu with a height threshold, if the hu exceeds the height threshold, shutting down for protection, if the hu does not exceed the height threshold, continuing to operate the dual-stage motion system.