Development of a Flexure Mechanism for Thin Die Pick-up Process

The capability of handling thin semiconductor chips during the pick-and-place process has become one of the major challenges in chip packaging process. When the chip becomes thinner, strength of the chip decreases dramatically and chip cracking increases, especially during the pick-up process. Traditional pin driving systems in the pick-up equipment that based on servo-motor and cam mechanisms are difficult to realize precise control of ejecting velocity and impact forces when peeling chips from the blue tape. The research presented in this paper aims at developing a pin driving system based on piezo-stack actuator and flexure mechanism for thin die pick-up process. First, the concept design of the piezo-driven flexure mechanism for the thin die pick-up process is established by comparison with traditional die pick-up equipment. Then, a bridge type flexure mechanism intended for the thin die pick-up process is designed and analyzed. The structure of the flexure mechanism is optimized through a parametric model using response surface method. A prototype of the mechanism is developed and tested. The experimental results are discussed. The flexure mechanism can finally achieve a displacement amplification over 9.