euspen SIG: Micro/Nano Manufacturing 2023

The authors used a laser focus sensor, originally intended to measure the vertical distance from the sensor to an object, to also measure the lateral distances between structures of a 40 µm pitch cross grid using a nanometre positioning system. The positioning system can move a platform in six degrees of freedom within a planar travel range of ⌀ 200 mm and is referenced by differential laser interferometers. A 4 nm standard deviation of cross grid center positions has been achieved over a range of 4 mm for the X and Y directions in the short term, and less than 20 nm standard deviation in the long term. Height measurements are also possible at the same time.