Defect analysis and lifetime evaluation of a release-coated nanoimprint mold

Nanoimprint lithography (NIL) is very useful technique for the fabrication of nanopatterns. In ultraviolet NIL, a release coating on the mold surface prevents the adhesion of the replicating resin. However, this release coating gradually deteriorates as the number of repetitions of NIL transfer increases. It is therefore important to evaluate the lifetime of the release agent. Measurements of the contact angle and release force are normally used in lifetime evaluation; however, these values do not clearly characterize the lifetime behavior because they tend to approach saturation as the number of repetitions increases. We introduce the error rate as a new means of evaluating the lifetime of release coatings. The error rate is derived by statistical treatment of transferred dots patterns. We found that mixing of various types of release agent is effective in reducing the error rate and, therefore, in increasing the lifetime of the NIL mold.