To fabricate high reliability Micro Electro Mechanical Systems (MEMS) devices, damage-free etching with high aspect three-dimensional (3D) structure is important. Plasma etching resulted in profile anomaly near high aspect 3D structure due to distortion of ion trajectory by distortion of ion sheath and degradation of mechanical property of MEMS devices due to defect generation by UV irradiation, respectively. Conversely, neutral beam was found to be a favorable technique to realize precise and damage-free etching for high aspect ratio and 3D MEMS structure.