Fabrication of SAW devices using SEM-based electron beam lithography and lift-off technique for lab use

This paper describes a micro-fabrication process developed for daily research work on SAW devices in the authors´ laboratory. The combination of SEM-based electron-beam (EB) lithography and lift-off process installed in a conventional laboratory without any particular cleaning facility is shown to be effective in fabricating well-defined IDT finger patterns with the line width of up to 180 nm in a half day at good yield. For the combination of the EB lithography and lift-off process, it is also shown how a very thin organic anti-static layer works well to avoid charge accumulation on a resist layer, which is easy to occur on insulating piezoelectric substrates and results in the EB diffraction. The present process was applied to the fabrication of SAW devices with various configurations including SHF resonators and single-phase unidirectional transducers. The result concludes how the process is useful for SAW research work in laboratories.