Electron Beam Recorder for Patterned Media Mastering

Patterned media are promising technologies to realize the next-generation hard disk drives (HDD) with an areal density beyond 1 Tbit/in.2. Two types of patterned media have been proposed: one is the discrete track medium (DTM) and the other is the bit-patterned medium (BPM). Both DTM and BPM require very small feature sizes and extremely tight tolerances. The mastering process is a key technology for production of patterned media, and electron beam mastering is the only means to carry out the process. We developed a new electron beam recorder (EBR) for patterned media mastering. In this paper, we introduce the technologies and the recording performance of the EBR. The EBR has four primary technical features: a 100 kV EB column, a high-precision r–θ stage system, a stage error correction system, and an EBR formatter for patterned media. In experimentals, the EBR demonstrated the following recording performance. The EBR achieved sufficient recording accuracy for the requirements of DTM with 1 Tbit/in.2 areal density. The EBR succeeded in high-density recording of a DTM pattern with 35-nm track pitch for over 1.5 Tbit/in.2 areal density. The EBR showed high throughput and good recording stability by recording a 1.8-in. DTM master. In this experiment, the EBR achieved a line width uniformity of less than 1 nm and a short exposure time of about 50 h for whole-area recording. We proved the practicality of the EBR for patterned media production.