Fabricating Method for Multilevel Interconnection with Differential Adhesion Strengths between Metal and Silicon Oxide Thin Films

This research demonstrates a newly developed technique to fabricate multilevel interconnections with differential adhesion strengths between metal and silicon-oxide (SiO2) thin films. In the field of micro electromechanical systems (MEMS), the various kinds of metals have been applied as functional materials, i.e. low resistance, high-temperature endurance, catalyst and so on. However, several kinds of metals are not applied on the SiO2 thin film, since an adhesion strength between metal and SiO2 thin films is not enough. Thus, the adhesion strengths (delamination energies) were estimated with a molecular dynamics simulation, and the metals of the lower wiring and the contact area were experimentally determined to easily fabricate the multilevel interconnections. Consequently, the Cr, Ti and Ni thin films can be applied as the adhesion layer on the lower wiring, and the Au and Cu thin films can be applied as the release layer on the contact area.