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Uwe Seifert & Carlos Mata, Qimonda AG, Dresden, Germany; Thomas Trautzsch & Martin Tuckermann, KLA-Tencor GmbH, Dresden, Germany; Aneesh Khullar, Jorge Fernandez & Catherine Perry-Sullivan, KLA-Tencor Corporation, California, USA

ABSTRACT

Defect monitoring plays a critical role in the drive to obtain high yield and fast ramp in advanced memory device fabrication. However, in order to maintain cost effectiveness and operational efficiency, inspectors implemented as part of a yield strategy must adapt to changing inspection requirements, and detect defects on numerous devices, varying materials and multiple technology nodes. Broadband DUV inspection capability was introduced to Qimonda’s Defect Density Group, making it possible to collect broadband brightfield inspection data on several memory layers covering multiple materials and design rules. These data demonstrate that the process materials, pattern geometries and design rules all affect the optical contrast of defects of interest and nuisance events. These data further show that a brightfield inspector with a tunable broadband illumination source, selectable optical apertures, and advanced defect binning capability, provides the flexibility required to solve varying memory defectivity issues and to meet changing yield monitoring requirements.