Method of forming a temporary test structure for device fabrication

Abstract

A method of forming a temporary test structure for device fabrication is provided. The method is particularly useful for electrically testing conductive interconnects during controlled collapse chip connections (C4) fabrication and/or through-silicon vias (TSVs) during interposer fabrication. The method includes providing a substrate containing a plurality of electrically conductive interconnects extending vertically to top surface of the substrate. A temporary test structure is formed to connect the plurality of interconnects and for electrical testing. The suitable material for the temporary test structure is TiW for a single layer structure, or Cu or Cu alloy over Ti or TiW for a bilayer structure with thickness in a range of about 20 nm to 1200 nm. Excimer laser ablation can be used to form the temporary test structure. Electrical testing is performed on the substrate by probing at different test locations on the temporary test structure. All or part of the temporary test structure is removed so as not to affect product performance, and the substrate can be further processed with normal processes. The temporary test structure may contain electrical test pads which provide a way to make temporary connections to small interconnect landings or features at extreme tight pitch to fan them out to testable pads sizes and pitches.