An enhanced system for automated wafer particle and crystalline defect inspection

Detecting and quantifying contaminants and defects on micro-electronic grade silicon wafer surfaces is extremely important to ensure high yield of Ultra Large Scale Integration (ULSI) devices. Laser Surface Scanning Inspection Systems (SSIS) have been widely used to automate wafer particle inspection process. Although automated particle inspection sensitivities are capable of detection below 0.100 mu m(1), visual inspection continues to be used in silicon wafer manufacturing facilities. Visual inspection is required because conventional SSISs are not capable of identifying and classifying a variety of crystalline defects such as dislocations, slip lines, stacking faults, voids, and mounds. This paper discusses a new inspection method of wafer particle inspection using an improved SSIS equipped with both a dark channel and a Reconvergent Specular Detection (RSD) light channel. This new inspection process provides the capability of successfully identifying and quantifying crystalline material defects as well as distinguishing them from particles; therefore, it provides the solution for fully automated wafer inspection. This paper will also discuss and compare the results of the new automated wafer inspection process and visual inspection.