Improved SRAM detection through scattered light collection

摘要

A new inspection scheme was proposed and demonstrated for enhanced sensitivity on SRAM patterns for 28nm DR, via ADI and SiGe DP layers. The scheme is based on tailored illumination and collection. The new inspection scheme has demonstrated higher sensitivity over scattered light and BF inspection. The ability to filter SRAM pattern increases the defects' SNR. The SNR increase enhances the CR of these defect types and enables capturing defects with lower signal.