Multifunctional contactless interconnect technology

Abstract

The present invention is a method for providing multifunctional, contactless, interconnect technology that can simultaneously fabricate four features on a silicon wafer within the same metallization level including a diffusion barrier layer, a trim element (fuse), a higher resistivity local interconnect/strap, and a lower resistivity global interconnect. The fabrication only requires two lithographic operations and one metal deposition. A first metal (a refractory metal) film having constant thickness is sputter deposited on the silicon wafer. In the preferred embodiment, the refractory metal is titanitun-tungsten. A second metal fihn may be sputter deposited on the first metal film. The first metal fihn has a higher resistivity than the second metal film. In the preferred embodiment, the second metal is aluminum-copper. Four features may be defined using a first mask. The features are etched and the first mask is removed. Three of the four features may be further defined using a second, non-critical mask. The second metal film of the three features are wet etched and the second mask is removed to provide the four features. An intermetal oxide is deposited. The present invention maintains good barrier integrity, even as devices are scaled down into the submicron and sub-half micron regimes.