Novel TAB inner lead bonding technology eliminating bump formation process

A novel tape automated bonding (TAB) inner lead bonding (ILB) technology, wherein an individual inner lead can be directly bonded with an individual bonding pad for ICs without using any gold bumps, was developed. The proposed ILB technology makes it possible to attain high density packaging as well as highly reliable connections. In addition, packaging costs can be drastically reduced, by eliminating the bump formation process. The key to successful direct connections, practical bond strength without causing any damage in the pad structure, is producing uniform vertical stress distribution on the bonding area during the bonding process. A newly developed bonding process and a specifically designed bond tool make it possible to produce uniform vertical stress distribution. A bondability study, involving pull tests on the bonded tape leads and high-temperature storage tests, was carried out. The results showed the viability of the proposed ILB technology as a reliable connection process. Basic bond tests for high density packaging were also attempted. It was ascertained that this technology has a great potential for fine pitch connections