An electrical test structure to evaluate linewidth variations due to proximity effects in optical lithography

A simple test structure is used in the investigation of linewidth variation at topographical edges. Preliminary qualititative results for electrical linewidth variations are presented and correlated with SEM inspection. A linewidth reduction is observed as the two features on different layers draw closer together and it is demonstrated that this approach is sensitive enough to enable lithography engineers to optimise resist processing to minimise this effect.