Non-Destructive Acoustic Metrology and Void Detection in 3x50μm TSV

摘要

Through Silicon Via (TSV) technology represents one key aspect of 3-D integration. International Technology Roadmap for Semiconductors (ITRS) has identified a need for an in-line metrology for characterizing voids in TSV structures. We have previously described a laser-based acoustic technique which can be used to detect voids in vias. Results for 10x100 and 5x50μm via structures were reported. In this work, we report on measurements of 3x50μm vias with aspect ratio of~17:1. Accuracy of the laser acoustic technique is validated by comparison with cross section images obtained using focused ion beam scanning electron microscopy (FIB-SEM). Measurements typically take a few seconds per site making this non-contact, non-destructive technology an attractive option for in-line void detection.