Study on a novel bond head with proportional electromagnet in chip operation

This paper presents the electromagnetic model and the experimental results of a novel bond head for chip operation. The existing bond head with spring or mechanical connection is difficult to achieve the purpose of protecting chips. The pneumatic bond head can´t timely feedback the force signal to control system. To increase the effective and safety of the die bonding, a bond head with the very fast response and steady bonding force is required. A constant-force bond head with proportion electromagnet is proposed. The magnetic force is studied using a FEM electromagnetic field model, and the structure parameters of bond head are optimized. A design is created that achieves a force error range of 1% in 0.3mm displacement. A prototype of the designed bond head is built. The bonding force measurements and system response time are tested to check the stability. The test results show that the calculated magnetic force agreed fairly well with the measured results, and the force error range of 1% is achieved.