Room-Temperature Cu–Cu Bonding in Ambient Air Achieved by Using Cone Bump

Abstract

We demonstrate room-temperature Cu–Cu bonding in ambient air by using a Cu cone bump in combination with a Cu electrode with a cross-shaped slit. By wedging the Cu cone bump into the cross-shaped slit, a bonded interface that is substantially free from contaminants can be formed. The cross-shaped slit gives lower connection resistance than a simple hole. The resistance per connection was approximately 83 mΩ.