Bismuth sodium titanate based lead-free ultrasonic transducer for microelectronics wirebonding applications

Bismuth sodium titanate based lead-free piezoelectric ceramic 0.885(Bi1/2Na1/2)TiO3–0.05(Bi1/2K1/2)TiO3–0.015(Bi1/2Li1/2)TiO3–0.05BaTiO3 (BNKLBT-1.5) rings (OD = 12.7mm, ID = 5.1 mm and 2.3 mm thick) were fabricated and characterized. Four ceramic rings were sandwiched between front and back metal plates to form a pre-stressed piezoelectric sandwich transducer and used as the driving element of an ultrasonic wirebonding transducer and the performance of the transducer was evaluated. The BNKLBT-1.5 transducer, when fitted with titanium front and back plates, was found to have axial vibration comparable to that of PZT transducer thus showing that BNKLBT-1.5 has the potential to be used in fabricating lead-free ultrasonic wirebonding transducers.