New technology for high-density LSI mounting in consumer products

The ongoing trend toward downsizing and the growing sophistication of electronic devices require increasingly higher LSI mounting densities. Flip-chip technology is used to mount LSIs without using wire and thus enables higher mounting densities than conventional mounting technology, which uses Au wire bonding. Fujitsu has developed a new high-density flip-chip mounting technology for use in consumer products to reduce size and improve performance. This paper describes the bump method, assembly process, reliability, and applications of this new technology. It also examines Fujitsu’s efforts to develop an ultrasonic assembly technology that achieves high throughput and reduced cost.