Novel prediction methodology for etched hole patterning failure

We have created a model that uses discriminant function analysis to predict failures in etched hole patterning of the type that induces an open-contact failure by using critical dimension scanning electron microscope (CDSEM) measurement values of after-development resist hole patterning. The input variables of the best model were found to be the resist hole CD, the difference in resist hole CD between that of the 50% secondary electron (SE) threshold and that of the 20% SE threshold, and ellipticity. The model indicates that a tapered resist profile is one of the main causes of the open-contact failure in etched hole patterning. The model is applicable not only to lithography process optimization but also to lithography process control, where the focus center of optical exposure at resist patterning is determined not only from the perspective of resist CD but also from the perspective of suppressing the failures of etched hole patterning.