Electrical localisation of full open defects in comb–meander–comb structures

Test structures are key elements to characterise and identify the main contributors to yield loss in wiring structures. Among such monitors, comb-meander-comb structures have been widely used owing to their simplicity and reduced number of pads. With continuous scaling of dimensions and use of copper in interconnections, open defects has arisen as the most common defect affecting the interconnection, focusing thus on an important part of the research effort. In fact, present electrical methodologies are able to detect, localise and predict the resistance of weak (resistive) opens. However, such methodologies are not able to locate full opens. This lack of information may be useful for faster ramp-up and yield improvement, among others. In this context, a simple electrical methodology to predict the location of full opens in comb-meander-comb structures is presented. Experimental measurements carried out in a 65 nm technology die corroborate the feasibility of the approach.