超声键合变频式超声波发生器的设计

Design for Frequency-modulated Ultrasonic Generator in Ultrasonic Bonding Field

用于超声键合工艺的超声波发生器是引线键合封装设备的主要装置,其作用是驱动换能器并使其处于谐振工作状态,多工作频率点是未来换能器发展的一个重要方向。传统超声波发生器不具备多频段频率跟踪功能,该文构建了一种变频式超声波发生器,可动态适应不同特性的换能器,具有通用、应用面广等特性。变频式超声波发生器基于嵌入式系统,采用快捷准确的直接数字频率合成(DDS)及锁相环(PLL)反馈方案,实现自动查找换能器各谐振频率以及频率自动跟踪功能。实践证明,变频式超声波发生器可以驱动各种不同谐振频率的引线键合超声波换能器,并达到换能系统工作时的快速锁相、准确锁频要求。

Ultrasonic generator for the ultrasonic bond process is the key system in lead bonding packaging equipment, its function is to drive ultrasonic transducer and keep it in resonance status, and its multiple working frequencies is the key application in the future. The traditional ultrasonic generator does not own the PLL function in a wide frequency range. This article constructs a type of frequency-modulated ultrasonic generator which is able to adapt transducers of different characteristic dynamically and has the highlight for general purpose and wide application. Basing on embedded system and applying agility dependable direct digital synthesizer （DDS） and phase locked loop （PLL） feedback scheme, frequency-modulated ultrasonic generator can find every resonant frequency of the transducer and keep frequency automatic tracking. The experimental results show that frequency-modulated ultrasonic generator is able to drive all of lead bonding ultrasonic transducer of different resonant frequency, and reach the design specification of fast and unerring phase locking.