Abstract
A novel bump formation technology for tape automated bonding (TAB) packaging, in which bumps are mechanically fabricated on inner leads for TAB tapes using the micro-press technique, has been developed. A dome-shaped bump, 70μm diameter and 26μm height, is formed on an inner lead by compressing the lead between a combination of a rigid punch and a die. This Micro-Press Bump technology, enables reducing packaging costs drastically, because bump formation can be carried out with only one simple procedure, without using any additional materials, such as gold, except for the leads. A bump formation apparatus involving piezoelectric actuator, which has ability for a high bump formation productivity, as well as highly accurate bump formation, has been newly developed. By optimizing bumping conditions, such as punch and die shape and punch-die clearance, highly accurate bumps, ±0.5μm height accuracy, have been fabricated.
