Metrology for Monitoring and Detecting Process Issues in a TSV Module

Abstract

For Through Silicon Via (TSV) module processing on 300 mm wafers, an extensive characterization of deliberately introduced deviations in process steps has been done, for the structure definition part, as well as the metallization and CMP parts. Using both a 5 × 50 and 10 × 100 μm (‘diameter’ × ‘depth’) TSV geometry, the detection of defects, such as the inclusion of plating liquid in the Cu matrix, and off-target dimensions, such as depth deviations and wafer-level non-uniformity, have been investigated with mass measurements, atomic force microscopy, X-ray transmission, and focused ion beam sample preparation. Correlation between these methods, advantages as well as limitations for detecting process deviations and small defects are discussed.