SAW Tags for the 6 GHz range and SAW devices for 2–5 GHz range produced with nano-imprint-lithography

At the last IEEE Ultrasonics Symposiun in Prague (2013) we have shown theoretically the feasibility of 6 GHz SAW-tags with acceptable performance. In this paper we report experimental results for this device. We have also used the Nano-Imprint-Lithography (NIL) for manufacturing a few different SAW test devices operating at the 2-5 GHz frequency range - delay lines (DL), reflective DL and sensors. Corresponding measurement data are presented. The frequencies higher 3 GHz, although inaccessible for SAW devices produced by optical lithography, represent great interest for many applications. NIL technology has a potential of cheap mass-production tool for SAW devices in this range. We have fabricated a number of prototypes 6 GHz SAW-tag devices using electron beam lithography on a 4-inch Lithium Niobate 128° cut substrate. Then e-beam writing is performed using a state-of-the-art, JEOL JBX-9500 and sequentially developed using a standard wet development method. Finally, 50 nm of Al is deposited and lift-off is performed, leaving the Al in the desires SAW ID-tag pattern. The NIL process consists of imprinting using a Imrio100 J-FIL process followed by a tailored dry development process and finally metallization and lift-off. Ultra-Wide-Band (UWB) reflective delay lines suitable for SAW senstor operation in 2 GHz-3 GHz range have been manufactured. The 6GHz devices have such attractive features as small size (0.9 × 2.0 mm²), loss level comparable with that of devices operating in 2.45 GHz ISM band, large information capacity because of available Ultra-Wide-Band of frequencies.