A redundant metal-polyimide thin film interconnection process for wafer scale dimensions

The expected defect modes, and the predominance of a single mode, for wafer-scale interconnections produced using typical thin-film processing techniques are discussed. A process using redundancy in the vertical direction to eliminate the dominant defect mode is presented with calculations illustrating potential yield improvements. Experimental results of an implementation of the redundancy technique using a lift-off process with polyimide dielectric are presented. The process uses a repeatable elemental step capable of producing signal layers, via studs, or reference planes while maintaining good planarity. The basic precepts of the redundant process are verified