Some answers to new challenges in optical metrology

The visible trend in the implementation of new technologies and creation of new products is the continuous reduction of feature sizes. However, in the same way as the feature sizes are decreasing, the theoretical and practical constraints of making them and ensuring their quality are increasing. Consequently, modern production and inspection technologies are confronted with a bundle of challenges. An important barrier for optical imaging and sensing is the diffraction limited lateral resolution. The observation of this physical limitation is of increasing importance, not only for microscopic techniques but also for the application of 3D-measurement techniques on wafer scale level. A further challenge is the reliable detection of imperfections and material faults within the production chain. This means in-line metrology/defectoscopy is a must for future production systems. Only the real-time feedback of the inspection results into the production process can contribute to a consistent quality assurance in processes with high cost risk. Moreover the reliable measurement of free form surfaces, both technical and optical, the assurance of the traceability and the certified assessment of the uncertainty of the measurement results are ongoing challenges. The challenges and the physical limitations are addressed here by new approaches for testing semiconductor structures with enhanced resolution, the measurement of aspheric lenses with increased flexibility and the inspection of micro components with improved traceability.