Development status of back-end process for UV-NIL template fabrication

摘要

Nano-imprint lithography (NIL) is eminently suitable for low cost patterning for nanostructures. As feature sizes of the UV-NIL templates are the same as the wafer patterns, there are enormous challenges such as writing and inspecting smaller patterns for NIL template fabrication. In our previous works, we achieved less than 16nm resolution with a 100keV spot beam writer and non CAR. We also reported optimization of metrology for NIL templates and the characterization of anti-sticking layers with scanning probe microscopies.Normally the template is made from a 6025 photomask blank. After the blank undergoes a process similar to the photomask process, it is diced into 65 mm × 65 mm size and four pieces, and then each piece is polished into its final shape. Therefore it becomes difficult to inspect and clean them, because 65 mm substrates are unfamiliar in photomask industry. In order to reach the step for mass-production of the templates, the development of "back-end process", which includes not only cleaning and inspection but also repair, dicing, polishing, and coating anti-sticking layers, is essential. Especially keeping low contamination level during dicing and polishing processes is one of the critical issues.In this paper, we report our development status of "back-end process" for NIL templates. Especially, we focus on the techniques of reducing adder defects during dicing process and improving cleaning capability.