Analysis and compensation of alignment error in laser scanning heat-mode lithography system

Abstract

Alignment error significantly influences the fabrication quality of micro/nano structures in laser scanning heat-mode lithography systems. This paper presents an effective compensation strategy to address this issue. A laser heat-mode lithography system is established with a tightly focused objective lens and a grid scanning strategy, achieving a minimum grid size of 6 nm. The factors affecting alignment accuracy are then analyzed from the perspectives of the positioning error, galvanometer scanning distortion and coordinate system inclination. Following this, a compensation strategy is proposed, which adjusts the coordinate system of the dual-galvanometer to compensate alignment error. Experiments demonstrate the effectiveness, significantly reducing the maximum alignment error from 92.4 nm to 8.4 nm, improving alignment accuracy by approximately 91%. Furthermore, the fabrication of various structures with a minimum linewidth of 150 nm further confirms the excellent alignment performance of the system and demonstrates the advantages of laser heat-mode lithography. This work provides flexible compensation strategies for improving alignment accuracy in the dual-galvanometer laser scanning lithography system, paving the way for advancements in systems based on direct laser writing or other step-stitching lithography techniques.