Expanded area metrology for tip-based wafer inspection in the nanomanufacturing of electronic devices

Abstract. Effective measurement of fabricated structures is critical to the cost-effective production of modern electronics. However, traditional tip-based approaches are poorly suited to in-line inspection at current manufacturing speeds. We present the development of a large area inspection method to address throughput constraints due to the narrow field-of-view (FOV) inherent in conventional tip-based measurement. The proposed proof-of-concept system can perform simultaneous, noncontact inspection at multiple hotspots using single-chip atomic force microscopes (sc-AFMs) with nanometer-scale resolution. The tool has a throughput of ∼60  wafers  /  h for five-site measurement on a 4-in. wafer, corresponding to a nanometrology throughput of ∼66,000  μm2  /  h. This methodology can be used to not only locate subwavelength “killer” defects but also to measure topography for in-line process control. Further, a postprocessing workflow is developed to stitch together adjacent scans measured in a serial fashion and expand the FOV of each individual sc-AFM such that total inspection area per cycle can be balanced with throughput to perform larger area inspection for uses such as defect root-cause analysis.