Commercialization of a high performance SML series electron beam resist for nano lithography

Electron beam lithography (EBL) enables the fabrication of nano-scale structures via the patterning of a thin film resist with a narrow beam of electrons. A pattern is then transferred from this 'mask' onto or into a substrate via lift-off (metallization) or etching processes respectively. EBL is now a standard tool in the nanotechnology industry, and particularly in nanoelectronics. EBL machines can cost anywhere from ~£100K to over £2M (e.g. Vistec EBPG +5000), and the industry is broadly split into two categories: low voltage machines that operate at 30KV and below (cheap), and high voltage machines that operate at 100KV (very expensive). The main advantage of the expensive high voltage machines is that they are capable of patterning an electron beam resist into smaller features, and with higher aspect ratios than the low voltage systems. A new electron beam resist called SML series resist has been developed at the University of Manchester to obtain large aspect ratios using low acceleration voltages. As described above, typically, large aspect ratio structures can only be achieved using 100KV EBL machines. However, the vast majority of EBL machines in use are of the low voltage variety and so the ability to fabricate high aspect ratio structures is not accessible to the majority of the EBL community. The SML series resist overcomes this issue and enables the fabrication of very high aspect ratio structures using low voltage machines.