Al electrodes fabrication technology for high-frequency and high-power durable SAW devices

Addition of Ti, Ge, and Zn to sputtered Al electrodes in order to obtain both high power durability and fine dimensional control in high-frequency SAW (surface acoustic wave) devices is investigated. Ti is shown to be more effective than Ge, Zn, and conventional Cu. Improvement of electrode durability to SAW power is related to the grain refinement and static stress incorporated by addition of Ti, Ge, Cu and by the sputter deposition. Investigation of fine dimensional control revealed that the electrodes with Ti addition resulted in smaller width deviation brought about by reactive ion etching a dyed UV-posi-type resist of the vertical wall; the deviation is 40% of that brought about with conventional wet etching.<>