Magnification calibration standards for sub-100nm metrology

With the semiconductor industry moving into the 65nm technology node, the metrology of the critical dimension (CD) becomes an important part for the industry. Metrology relies not only on the precision, but also on the accuracy of the tools like the high performance CD-SEMs. A major area of concern affecting the accuracy of the high performance CD-SEMs is the magnification calibration. The purpose of the research is to address this area of concern by fabrication of magnification calibration artifact by using direct write electron beam lithography. A calibration artifact has been fabricated in negative resist Hydrogen Silsesquioxane (HSQ) onto a silicon substrate, thereby decreasing the contamination on the substrate. The design of the artifact has been corrected for the proximity effects, giving a 2-D dense grid structure with 100nm pitch. Pitch determination using optical metrology tools and the inbuilt laser interferometer in the electron beam lithography tool is being evaluated for making the artifact traceable to some national standards. Once the traceability is achieved, mass production at low cost using Nanoimprint technology is feasible.