The study of contact hole MEEF and defect printability

We have optimized the standard method for the extraction of MEEF at 200nm contact hole with regard to the pitch and mask CD variations, which resulted in 4.8. Additionally, we have evaluated the impact of mask bias, surrounding pattern size and asymmetric change of mask CD. The pitch has greatly influenced the MEEF of the contact hole, and the contact holes with the minimum pitch show higher MEEF than isolated or semi-dense contact holes. The MEEF was little affected by the mask bias, ranging from 10 to 30nm. The MEEF remains independent despite the changes of the mask CD occurring around the holes within ±10nm range. The variations of the mask CD in one direction or another are not related to the MEEF determination. In addition, the pitch has influence on the defect printability. Other things that influence the defect printability are the defect types and their location. The defect of Cr intrusion has more intensive effect on the printed CD change. The more the defect is close to the center of the hole pattern, the more the defect printability increases.