Development of a media actuator for probe-based data storage

Nanoscale data bits can be written and read with micromachined scanning probe microscopy (SPM) probes. Since a large number of probes can be integrated on a single chip by micromachining batch process and operated simultaneously, probe-based data storage with small form factor can have very large data capacity and good data transfer rate compared with current mobile storages. One of barriers to realizing probe storage is to fabricate a reliable media actuator using micromachining process. In this paper, we report the microfabrication of an electromagnetic actuator and the results of evaluation test. The actuator consists of a media substrate, a silicon frame, four pairs of magnets, a spacer, and a printed circuit board (PCB). The silicon frame was fabricated with conventional micromachining process and the design of PCB was optimized to reduce power consumption during operation. The total size of device after integration is 17.3 × 17.3 × 0.8 mm3 while the media area is 12.8 × 12.8 mm2. The measured displacement of actuator is ±50 μm for input current of ±111 mA at the average power consumption of 24.4 mW and the resonance frequency is 69 Hz. The resolution of electromagnetic actuator was evaluated with conventional atomic force microscopy (AFM). From the images at a small scan range, we can conclude the resolution of the actuator is below 10 nm.