A 6-DOF micro-motion mechanism for wave aberration compensation of photolithography projection objectives

To address the high-precision adjustment requirements of wavefront aberration compensation in reflective lithographic objectives, this study develops a six-degree-of-freedom (6-DOF) mirror adjustment mechanism based on a Stewart platform. The mechanism utilizes six compliant legs to achieve 6-DOF micro-motion of the mirror mount. A kinematic decoupling model was established using a fixed-angle XYZ coordinate framework and spatial geometric analysis to achieve decoupling of leg actuator displacements. An experimental prototype was constructed to validate the model and assess translational performance. Results show that the system achieves a translational positioning resolution of 0.1μm within a ±100μm range. The relative error between theoretical and experimental leg actuator displacements was limited to 5.88%, 6.34%, and 6.62% along the X, Y, and Z axes, respectively, with minimal cross-axis interference. The mechanism demonstrates precise, low-coupling control, offering both theoretical and experimental support for future applications in high-precision optical adjustment and wavefront aberration compensation.