Stress analysis of "Micro-Bump Bonding" structure for "Chip on glass" packaging

Abstract

Micro-Bump Bonding (MBB) method makes possible the micro-order direct bonding between IC electrode and circuit substrate electrode. The technology consists of three elements: an IC chip with bumps, a circuit substrate, and a bonding adhesive. The binding forces of the applied adhesive accomplish electrical connection between the bumps on the IC chip and the electrodes on the substrate. Stress analysis is made to estimate the contact force that the adhesive imposes to drag together the bumps of the IC and the electrodes of the substrate. An elastic model is assumed herein to determine the stress characteristic of the MBB structure. The stresses of the structures with gold bumps and compliant bumps are compared at various temperatures. Such a stress analysis is helpful in determining which kind of bumps is more suitable for a given MBB structure.