A large-travel hybrid metrology platform integrating laser focus sensor and atomic force microscopy

Abstract

Abstract Modern micro- and nanoscale manufacturing requires traceable multi-scale metrology spanning macroscopic geometries and sub-micrometer features. Singlesensor systems are limited by trade-offs between resolution, speed, and measurement range. This work presents a hybrid platform integrating an optical microscope, laser focus sensor (LFS), and atomic force microscope (AFM) on a six-degrees-of-freedom (6-DOF) nanopositioning stage, enabling inspection within a Ø200mm × 25mm workspace. A multi-stage alignment protocol ensures lateral repeatability through optical-to-mechanical verification, coordinate transformation, and edge-feature cross-correlation. Experiments on a patterned ultra-low expansion (ULE) substrate demonstrate consistent centroid localization between LFS and AFM, with standard deviations below 100nm. Residual discrepancies, attributed to different sensing principles, remain stable over time. The system enables hierarchical inspection through optical guidance, large-area LFS scanning, and targeted AFM analysis, supporting future scalable in-line metrology for semiconductors, micro-optics, and microelectromechanical systems (MEMS) applications.