Motion performance measurement and optimization of motorized stages using tightly focused laser marking

Motorized stages are widely used in the fields of processing and measurement, such as lithography, semiconductor packaging, biochips, and micro/nanostructure characterization. We propose a tightly focused laser marking method for measuring the motion performance of motorized stages. In this method, a test sample is coated with heat-mode resist thin films and is fixed onto motorized stages. A tightly focused laser spot with a size of ∼520 nm irradiates the heat-mode resist thin films, which then absorb the laser energy and are heated. A laser-induced marking of the films' structural change from an amorphous state to a crystalline state occurs when the temperature exceeds the crystallization threshold temperature. The motion locus and performance of motorized stages can be clearly observed via the marking of the structural change of heat-mode resist thin films, which can be further clarified through the lithography developing process in alkaline or acidic solutions. The measurement results showed that the minimum nonuniformity coefficient of the motorized stages was 0.016, the minimum parallelism error was 80 nm, the minimum positional accuracy was 0.76 μm, and the accuracy of the measurement system was within 80 nm. The test results demonstrate that the motorized stage can achieve high-precision uniaxial motion with a period of 300 nm and biaxial coordinated motion with a period of <3 μm through parameter optimization, thereby reaching its ultimate performance. Compared to the non-interferometric methods, this tightly focused laser marking method has the advantages of strong environmental adaptability and high accuracy. This study provides an effective and convenient approach for the measurement and optimization of the motion performance of motorized stages.