A High-Efficiency Searching Time Reduction Method for VCM Soft-Landing Operation During Chip Bonding

Abstract

The chip precision bonding operation is a large-stroke high-speed and high-acceleration operation, which is usually realized by a voice-coil-motor (VCM). During the decelerating positioning to contact the chip, such high-dynamic movement could often accompanied by inertial vibration which may impact the chip. To achieve a gentle contacting, the VCM soft-landing method is widely used in bonding process, which designs a micro-searching-area to accommodate the inertial vibration, and starts up a low-speed uniform-motion once the bonding system stabilizes. To minimize the time consumed in the searching area, this work proposed a high-efficiency searching time reduction (HSTR) method. Specifically, during the entire inertial vibration, a dynamic uniform-motion actuation, which is conditionally planned for the VCM, starts the uniform-motion as early as possible, and arrives at the target position precisely when the vibration attenuation is completed. The start-up moment planning is determined by the inertial vibration cycle, while the actuation velocity planning is dynamically decided by the real-time inertial vibration energy. The HSTR method can perform a proper actuation to speed up the VCM soft-landing without affecting the gentle contacting. Together with theoretical verification of its implementation and effectiveness simulation, the HSTR method is validated experimentally with different displacements, velocities, and accelerations.