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Product Briefing Outline: Rudolph Technologies has launched new ‘E30’ and ‘B30’ modules for wafer edge and backside inspection. The third-generation E30 and B30 modules provide improved sensitivity while maintaining high throughput, making them suitable for production environments. The new tools are equipped with the performance enhancements needed for inspection and in-line monitoring of 32nm manufacturing processes from front end of line (FEOL) through final manufacturing. The first shipments are scheduled for 4Q08.

Problem: With the growing use of immersion lithography at the 45nm node and below, greater attention is required to monitor particle contamination after each lithography step at the wafer edge and wafer backside.  Interactions of the wafer and scanner through the immersion medium introduces a number of novel defectivity modes, several of which are edge-specific. Although edge defects typically do not cause yield loss directly, they are often precursors to killer defects in the wafer's active area. Real-time edge inspection ensures that edge defects can be detected, and their causes can be corrected, thereby minimizing yield impact.

Solution: Both modules use image-based inspection to provide a much richer data set than light scattering techniques; it enhances accuracy in sizing, locating and classifying defects. The E30’s improved darkfield capability increases its sensitivity to 2µm, while its ability to suppress the signal from the pattern allows inspection of production wafers. Recipe-controlled illumination greatly simplifies system use. Like its predecessors, the E30 module also provides metrology capability for the edge-bevel profile, multi-film edge bead removal and bevel clean processes.

Applications: Wafer edge and backside FEOL and BEOL inspection at the 32nm node.

Platform: The edge and backside inspection capability can be combined in a single cabinet. While the E30 and B30 modules are part of the all-surface ‘Explorer’ Inspection Cluster, they can also be used with the ‘NSX’ Series inspection systems commonly used in outgoing quality assurance and back-end fab applications.

Availability: September 2008 onwards.