Published online by Cambridge University Press: 01 February 2011
This study discusses topography specifications for 22 nm and beyond CMP process and presents recent experimental data. We evaluated local topography impact on CD development in the subsequent layer using specially designed 22-nm test patterns. A wide range of localized erosions were generated in CMP within a single exposure field to avoid any focus-correction effect by the scanner or any other scanner-induced focus change between different levels of local erosion. Local erosions were measured by atomic force microscopy (AFM) after each process step from CMP to lithography to identify the local planarization effect from other film coatings between CMP and lithography. Post-litho CD inspection was done in the subsequent layer over the local erosion areas. Using experimental results, the paper also discusses BEOL pattern design rule for maximizing the process window.