Hitoshi Komuro

Improvement of optical proximity-effect correction model accuracy by hybrid optical proximity-effect correction modeling and shrink correction technique for 10-nm node process

Abstract. The model accuracy of optical proximity-effect correction (OPC) was investigated by two modeling methods for a 10-nm node process. The first method is to use contours of two-dimensional structures extracted from critical dimension-scanning electron microscope (CD-SEM) images combined with conventional CDs of one-dimensional structures. The accuracy of this hybrid OPC model was compared with that of a conventional OPC model, which was created with only CD data, in terms of root-mean-square (RMS) error for metal and contact layers of 10-nm node logic devices. Results showed improvement of model accuracy with the use of hybrid OPC modeling by 23% for contact layer and 18% for metal layer, respectively. The second method is to apply a correction technique for resist shrinkage caused by CD-SEM measurement to extracted contours for improving OPC model accuracy. The accuracy of OPC model with shrink correction was compared with that without shrink correction, and total RMS error was decreased by 12% by using the shrink correction technique. It can be concluded that the use of CD-SEM contours and the shrink correction of contours are effective to improve the accuracy of OPC model for the 10-nm node process.

Hybrid OPC modeling with SEM contour technique for 10nm node process

Hybrid OPC modeling is investigated using both CDs from 1D and simple 2D structures and contours extracted from complex 2D structures, which are obtained by a Critical Dimension-Scanning Electron Microscope (CD-SEM). Recent studies have addressed some of key issues needed for the implementation of contour extraction, including an edge detection algorithm consistent with conventional CD measurements, contour averaging and contour alignment. Firstly, pattern contours obtained from CD-SEM images were used to complement traditional site driven CD metrology for the calibration of OPC models for both metal and contact layers of 10 nm-node logic device, developed in Albany Nano-Tech. The accuracy of hybrid OPC model was compared with that of conventional OPC model, which was created with only CD data. Accuracy of the model, defined as total error root-mean-square (RMS), was improved by 23% with the use of hybrid OPC modeling for contact layer and 18% for metal layer, respectively. Pattern specific benefit of hybrid modeling was also examined. Resist shrink correction was applied to contours extracted from CD-SEM images in order to improve accuracy of the contours, and shrink corrected contours were used for OPC modeling. The accuracy of OPC model with shrink correction was compared with that without shrink correction, and total error RMS was decreased by 0.2nm (12%) with shrink correction technique. Variation of model accuracy among 8 modeling runs with different model calibration patterns was reduced by applying shrink correction. The shrink correction of contours can improve accuracy and stability of OPC model.