Fabrication of sub-wavelength size aperture for nearfield optical probe on cantilever

The nanosize silicon oxide aperture on the cantilever array has been successfully fabricated as a near-field optical probe. Various semiconductor processes were utilized for sub-wavelength size aperture fabrication. The anisotropic etching of the Si substrate by alkaline solutions followed by anisotropic crystal orientation-dependent oxidation, anisotropic plasma etching and isotropic oxide etching was carried out. The 3 and 4 micron size dot arrays were initially photolithographically patterned on the frontside of the Si[100] wafer. After fabrication of the V-groove shape by anisotropic TMAH etching, the oxide growth at 1000°C was performed to have an oxide etch-mask. The oxide layer on the Si[111] plane has been utilized as an etch mask for plasma dry etching and water-diluted HF wet etching for nanosize aperture fabrication. The Au thin layer was deposited on the fabricated oxide nano-size aperture on the cantilever array. The (5×1) NSOM array with 130 nm metal aperture was successfully fabricated.