Full-wafer post-via wet clean nonvisual defect inspection

摘要

The optimization of wet clean and surface preparation processes is an industry challenge, due in part to the lack of adequate inspection techniques to detect nonvisual defects (NVD). This article describes how a novel, nonopticai inspection technique was used to optimize an existing post-via wet clean process. A scanning differential work function technique detects submonolayer NVDs, allowing for an increase in die yield due to the elimination of residual cleaning media, and a reduction in cost through shorter rinse times and lower water consumption.