Addressable test structure design enabling parallel testing of reliability devices

Abstract

This new design enabled an efficient layout of breakdown test devices for parametric and reliability testing. These reliability circuits consisted of interlocking combs of routing layers with varying widths and spaces that were representative of the design rules. These were accessed through multiplexer controlled pass gates. All addresses could be simultaneously enabled for stress biasing and addressed individually for failure detection. Once a breakdown was detected, as current leakage of the comb, each device could be addressed sequentially to find the failing structure. This was an improvement over previous designs which either grouped many devices in parallel, but could not electrically identify which device was failing, or only had a single device enabled, but suffered from poor pad efficiency. The grouping of these devices allows for simultaneous parallel stressing of each force and ground pad pair on the parametric testers. Electrical measurement showed that the same breakdown voltage values measured on this mux design were the same as standalone devices.