Extracting Defect Density and Size Distributions from Product ICs

Abstract

Defect density and size distributions (DDSDs) are important parameters for characterizing spot defects in a process. This article addresses random spot defects, which affect all processes and currently require a heavy silicon investment to characterize and a new approach is proposed for characterizing such defects. This approach presents a system that overcomes the obstacle of silicon area overhead by using available wafer sort test results to measure critical-area yield model parameters with no additional silicon area. The results of the experiment on chips fabricated in silicon confirm the results of the simulation experiment that DDSDs measurement characterizes a process in ordinary digital circuits using only slow, structural test results from the product