New Au-Al interconnect technology and its reliability by surface activated bonding

In this paper, a new interconnect method, surface activated bonding (SAB), for microelectronic systems is introduced. The bonding is carried out at room temperature which is different from the traditional technology such as wire bonding. The interconnect is achieved just by the contact of two atomically clean surfaces, prepared by a fast atom beam. SAB is especially suitable for high reliability, compact and high density systems which would be more difficult to be realized by other interconnect methods because of relative high bonding temperature, wide pitch and long signal transferring distance. A Si substrate with Au bumps on the top and a Si chip with patterned Al film on the surface were prepared to test Au-Al bonding feasibility and the reliability of the SAB method. Satisfactory experimental results were achieved.