Optimal design of micro-force sensor for wire bonding with high acceleration and frequent movement

The wire bonding is the mostly used process in chip packaging, which requires micro-force sensor and micro-force control to perform the bonding task with high frequency no less than 15 Hz. This paper presents a new strategy of active control methodology based on the linear motor (used as actuator). The novel methodology of optimal design for the 0.001 N-resolution micro-force sensor under the condition of high acceleration and fast movements is detailedly elaborated on the basis of analyzing the influence of the acceleration on force sensor. The transfer function between the bracket input and the output force of the double-beam cantilever force sensor is finally derived. The experiments proved that the intrinsic frequency of the double-beam cantilever is much higher than that of the single-beam cantilever with same sensitivity, which improved the system bandwidth and effectively solved the contradiction between the high sensitivity requirements of softness and the high accuracy position control requirements of rigidity of the micro-force sensor system.