The design and control of a jetting dispenser for semiconductor electronic packaging driven by a piezostack and a flexible beam

This paper presents the performance characteristics of a new type of jetting dispenser which can be applicable for modern semiconductor packaging processes. The proposed jetting dispenser is driven by both a piezostack actuator and a flexible beam mechanism. After describing the geometric configuration and operational principle of the dispenser, a mathematical model of the system is derived by considering the dynamic behaviors of structural parts such as the piezostack, the flexible beam, the needle structure, and the adhesive fluid dynamics. In the modeling, a lumped parameter method is employed and the governing equation of the whole dispenser is then formulated by integrating the structural model with the fluid model. Based on the proposed model, significant structural components of the dispenser such as the piezostack, the flexible beam, and the actuating spring are designed in order to achieve operational requirements (needle motion amplitude: up to 0.4 mm; operating frequency: up to 700 Hz). Subsequently, dispensing performances such as the dispensing dot size and flow rate are experimentally evaluated. In addition, a control algorithm is designed and empirically realized to demonstrate some benefits of the proposed jetting dispenser such as accurate controllability of dispensing amount.