Low Temperature Wafer Bonding by Copper Nanorod Array

A vast array of Cu nanorods with a diameter of grown by an oblique angle deposition technique was utilized as an adhesive layer for bonding Si wafers at low temperatures. The focus ion beam∕scanning electron microscope images illustrate that the Cu nanorod array underwent coalescence readily upon a bonding temperature at . Upon , a dense Cu bonding layer with homogeneous structure was achieved. A fully dense bonding structure was also obtained upon a lower bonding temperature at followed by a postannealing at in a reducing ambient.