This paper demonstrates the investigation of micro-fabrication methods for the development of W-band interaction structure. Vacuum Electron Devices (VED) based high-frequency and high-power sources consists of three major components namely, electron gun, interaction structure, and spent beam collector. The interaction structure is an important component for high-power generation and its dimensions reduces with increase in the frequency. Therefore, it becomes very challenging to develop this sub-mm interaction structure with stringent fabrication tolerances (<10 microns) and good surface finish (<100 nm). Hence, this paper presents a comprehensive investigation into different micro-fabrication methods aimed at optimizing the performance and development of W-band interaction structure within the limits of desired fabrication tolerances and surface finish. The results indicate the hybrid approaches, combining multiple fabrication techniques, offering significant advantages in achieving the desired precision and performance. The work done will be useful in the development of vacuum electronics based micro structures for high-power THz generation.