XY-Stage-based electron-beam recorder for the single-carrier independent Pit-edge recording radial partial response format

An electron-beam recorder in an XY-stage-based architecture was developed for mastering optical disks. The recorder uses the single-carrier independent pit-edge recording radial partial response (SCIPER/RPR) format. An electron beam is irradiated onto a master disk on continuously moving X and Y stages that are controlled so as to draw circular traces in sine and cosine waveforms against time, respectively. High-accuracy pit recording was realized using electron-beam deflection with feedforward correction of stage positioning error. A 25-Gbit/in2 SCIPER/RPR read-only-memory test disk with an alternating pit-array pattern was fabricated using the recorder. The pit-edge accuracy was evaluated from a scanning-electron-microscope image of the pattern. The obtained accuracy values were 1.6 nm (σ) for mark pitch, 3.5 nm (σ) for track pitch, and 3.8 nm (σ) for index position, which are good values for 3-level pit-edge modulation with 30-nm steps.