Vibration compensation platform for robot-based nanoscale measurements

Abstract

Measuring properties at the nanometre scale such as topography, morphology and roughness within a production line becomes increasingly important for quality control and process monitoring tasks. In a production line, ground vibrations are transmitted to the sample and the inspection tool, corrupting nanoscale measurements by affecting the distance between inspection tool and sample. To enable nanometre scale measurements a mechanism is needed that keeps this distance constant. This paper describes the concept and experimental results of a metrology platform that tracks the sample for nanoscale inspection. The nano inspection tool is carried by the metrology platform and is artificially coupled to the movement of the sample by using a feedback controller. A one degree of freedom experimental setup was built for demonstrating tracking performance. The implemented closed loop control achieves disturbance rejection with a bandwidth of 410 Hz and reduces emulated on-site vibrations from ±500 nm down to ±9 nm, showing significant reduction of external vibrations.