Harp test structure to electrically determine size distributions of killer defects

To improve accuracy of electrically based measurements of defect densities and defect size distributions, we present a novel harp test structure (HTS). There, horizontal and vertical parallel lines will be placed inside a given boundary pad frame without using any additional active semiconductor devices. The enhanced two-dimensional (2D) permutation sequence provides that all neighborhood relationships of adjacent test structure lines are unique. This is the key to disentangle even multiple faults detected by fast digital measurements. For this reason, the number and size of individual defects will be extracted anywhere inside or in-between layers. Experimental results show, that not only optical measurements, but also electrical measurements at a harp test structure are sufficient to get a precise defect size distribution that enables size distribution modeling for yield prediction