3D Atomic Force Microscopy as an Alternative to X-SEM and TEM for Advanced Process Metrology

As increasing demand for smaller device feature data drives wafer development costs up, process developers seek new metrology solutions to better address today's stringent process requirements. Traditional, destructive measurement techniques such as cross-section scanning electron microscopy (X-SEM) and transmission electron microscopy (TEM) are labor- and cost-intensive methods whose long turnaround times are not suitable for integration into process flow. Optical techniques, meanwhile, although suited for on-line metrology simply do not provide sufficient direct information and require cross-checking with accurate metrology to verify models.

Atomic force microscopy (AFM), on the other hand, represents an excellent solution for advanced process metrology. The Digital Instruments Dimension™ X3D Automated Atomic Force Microscope from Veeco is able to deliver TEM-like performance at a fraction of the cost. The X3D reduces cost per wafer pass by a factor as high as 10 and provides a return on investment after only 500 to 1000 cross-sections performed (i.e., by X-SEM or TEM). Furthermore, this nondestructive instrument is designed for in fab use for process control. Numerical results and data are available within minutes.