| With the rapid development of the semiconductor industry, MEMS devices is develop to the direction of high integration and high precision, and make a high demands of packing technology. The technique of wire bonding is the key of the MEMS encapsulation process, and the generator of ultrasonic is the core components of the wire bonding machine. The ultrasonic generator can output the ultrasonic signal that it is matching with the ultrasonic transducer and makes the ultrasonic transducer resonance. The ultrasonic transducer which is in resonance can converts electrical energy into mechanical energy efficiently. The mechanical energy can make a stable and reliable lead connection with interaction of heat and pressure. The performance of a ultrasonic generator determine the energy conversion efficiency of the transducer and have very important influence for bonding quality.The object of this paper is a research and design of the ultrasonic generator which is used in Automatic Wire Bonding Machine. The paper’s research content mainly includes the following aspects:(1) The equivalent resonance model of ultrasonic generator was established. In order to provide theoretical basis for ultrasonic generator design and analysis the characteristics of series and parallel resonant, the equivalent circuit was established in Lumped Parameter Method.(2) The circuit of ultrasonic generator was designed by the characteristic of ultrasonic transducer. The circuit was divided into some parts. Each part had its own function to meet the requirement of the technical specifications of the ultrasonic generator.(3) According to the request of wire bonding process, the output parameter of the ultrasonic generator was analyzed and the mathematical model of the real-time track of phase-locked loop circuit was established. The procedure of resonance frequency scanning, resonance frequency automatic locking, and communication between each model was programmed carefully to make the output of the ultrasonic signal stable and reliable.(4) The performance of the ultrasonic generator was tested and the program was debugged. Each model was tested so that they can be put together and work properly. Based on the actual bond requirements, the system was optimized. |
