On-wafer defectivity analysis of UPW with successive spin drying
Date published: 2022
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Ultrapure water (UPW) is extensively used for cleaning and dilution purposes in fabs. A problem in UPW can have a fatal effect on wafer defectivity so that the final die yield. Therefore, it is crucial to characterize the risk of on-wafer defectivity of UPW at different stages of purification. The current 12-inch wafer testing methods are capital intensive requiring special equipment for both sample preparation and on-wafer particle scanning. Therefore, extensive application of on-wafer analysis of UPW is not a financially viable solution. This presentation will introduce a practical and economically feasible methodology to analyze the on-wafer defectivity of UPW using small wafers (2-inch or 4-inch). The method is based on applying the spin-drying process successively on the same wafer, increasing the particle density to a level higher than the existing particle baseline of the wafer.
Authors: Ali Altun;
Tags: UPW; Wafer Defectivity; Particles; High Purity Chemicals