A 2-DOF piezoelectric platform for cross-scale semiconductor inspection

To address the challenge of achieving extensive travel and high precision in semiconductor inspection, this study proposes a novel 2-DOF cross-scale piezoelectric positioning platform. In semiconductor inspection, the platform utilizes elliptical, stick-slip, and direct-push drive modes to meet the motion requirements at millimeter, micrometer, and nanometer scales. By applying defined electrical signals to the piezoelectric units, the platform can achieve high-speed continuous mode (HCM) for the millimeter scale, low-speed stepping mode (LSM) for the micrometer scale, and high-precision positioning mode (HPM) for the nanometer scale. Theoretical analysis and simulations were performed to design the flexible stator of the platform, and its dynamic characteristics were analyzed. A prototype was fabricated, assembled, and experimentally tested to investigate the mechanical performance of the proposed platform. The results show that the prototype successfully realizes cross-scale motion in the three modes: achieving a maximum no-load speed of 62.47 mm/s in HCM, a low-speed stepping motion of 14.62 μm/s in LSM, and high-precision positioning with a resolution of 25 nm within a range of ±21 μm in HPM. Through the flexible switching and cooperation of the three drive modes, the platform can quickly approach the target at millimeter speed, further approach with micrometer step motion, and finally achieve nanometer precision positioning. Finally, the positioning platform was successfully applied to inspect semiconductor devices for defect inspection. This study explores a novel cross-scale driving method for piezoelectric positioning platforms, which provides a new approach for precision manipulation research related to semiconductor component inspection.