Advanced Lithography for Bit Patterned Media

For bit patterned media (BPM) applications, while significant progress has recently been made in demonstrating high-resolution dot patterning using e-beam direct writing, and followed by the successful imprint process, many serious issues in fabrication still remain. This paper will only discuss the key challenges in the BPM lithography, including (1) the commercial availability of a high-resolution rotating stage e-beam system; (2) the approach and limitation of directed polymer self-assembly for resist pattern quality improvement and resolution enhancement; (3) the difficulties and limitations in the fabrication and replication of a 1 times template with a density beyond 1 Tbit per square inch (Tb/in²), while the defectivity, lifetime, and damage of the template are still questionable; (4) the tight requirements of size uniformity and placement accuracy; and (5) the needs of advanced metrology associated with the very small dot size and defect characterization. In this paper, we will address the above challenges and present some experimental data along with possible solutions for the challenges.