


Automated optical measurements for statistical evaluation are possible with the Confovis AOI WaferINSPECT 305, a confocal measuring system equipped with objectives ranging from 2.5x to 100x magnification. Single wafers in sizes 4", 6", and 8" can be loaded onto the automatic vacuum stage. In manual mode, individual chips can also be characterized. The system captures up to 20 optical planes per second, performing a contrast evaluation to automatically determine the focus point. Wafer layout/geometry can be learned to perform automated measurement tasks, enabling both 2D and 3D measurements. The measurement results can be output as a wafer map during automated measurements, allowing quick capture and analysis of changes across the entire wafer. Examples include focus/dose variations or the investigation of inhomogeneities in etching processes. The height resolution is up to 3 nm according to VDI 2655, and laterally a resolution of up to 267 nm according to Rayleigh can be achieved. The Cognex software operating in the background enables, through AI-supported image recognition, not only the automatic measurement of geometric structures but also defect detection using the Golden Sample method. Overlay measurements for controlling successive lithography layers represent another application.
Highlights:
- Automated confocal measuring system
- 2D and 3D imaging and statistical evaluations across the entire wafer
- Overlay evaluations for quality control of successive lithography layers
- AI-supported image recognition via Cognex software
- Defect detection using the Golden Sample method