Development of smart transducer with embedded sensor for automatic process control of ultrasonic wire bonding

  • Or, Siu Wing (Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University) ;
  • Chan, Helen Lai Wa (Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University) ;
  • Liu, Peter Chou Kee (ASM Assembly Automation Ltd.)
  • Received : 2003.10.23
  • Accepted : 2004.07.27
  • Published : 2005.01.25


A ring-shaped lead zirconate titanate (PZT) piezoceramic sensor has been integrated with the Langevin-type piezoceramic driver of an ultrasonic wire-bonding transducer to form a smart transducer for in-situ measurement of three essential bonding parameters: namely, impact force, ultrasonic amplitude and bond time. This sensor has an inner diameter, an outer diameter and a thickness of 12.7 mm, 5.1 mm and 0.6 mm, respectively. It has a specifically designed electrode pattern on the two major surfaces perpendicular to its thickness along which polarization is induced. The process-test results have indicated that the sensor not only is sensitive to excessive impact forces exerted on the devices to be bonded but also can track changes in the ultrasonic amplitude proficiently during bonding. Good correlation between the sensor outputs and the bond quality has been established. This smart transducer has good potential to be used in automatic process-control systems for ultrasonic wire bonding.


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