Parallel Recording Array Head of Nano-Aperture Flat-Tip Probes for High-Density Near-Field Optical Data Storage

Increasing the memory capacity and data transfer rate of optical data storage to match the market requirements is now a challenging task. To realize a more effective and simple memory system, a parallel near-field optical system has been proposed using vertical cavity surface emitting laser (VCSEL) microprobe array heads. The concept, structure and fabrication process of new flat-tip microprobe arrays have been discussed and realized by the preparation of a silicon probe array in this research. Flat-tip probes are advantageous for improving optical properties since they are prepared from materials of high refractive index and the array shows good structural design for the contact head system with good uniformity of the probe height. We have successfully prepared Si nano-aperture probe arrays with the aperture size of 150 to 500 nm using microfabrication techniques, including photolithography, wet chemical etching, and a newly developed aperture formation process which uses a SiO₂ mask layer. The microstructural observation of Si fiat-tip probe-arrays is in good agreement with our design concepts and supports the strong possibility of their application to actual recording heads. We are now developing a monolithic nano-aperture VCSEL probe to complete our parallel near-field optical system with high memory capacity and fast transfer rates in the near future.