We introduce a novel fabrication technique for thin film devices, utilizing Focused Ion Beam micro-machining. Unlike conventional methods requiring post processes such as etching or solvent treatment, this method involves creating a pre-patterning step-like structure on the substrate before growing the thin film, achieving the desired device pattern right after thin film deposition. As an example, we fabricated devices with VO2 thin film of which electrical transport properties are examined. The VO2 devices exhibit robust metal-insulator transition behavior and V-I characteristics, indicating the high quality of the patterned devices. The results indicate that our approach enables intricate patterning, comparable to conventional e-beam lithography, without the risk of sample degradation. The simplicity, stability, and versatility of this technique suggest new possibilities for thin film device fabrication. © 2024 Korean Physical Society