US Patent 7862756 Imprint lithography

A method of making a substantial replica of a first imprint template which bears a first pattern is disclosed. The method includes filling recesses of the first pattern with a first material, removing the first material from the first imprint template to form a second imprint template which bears a second pattern, the second pattern being the substantial inverse of the first pattern, filling recesses of the second pattern with a photo-curable medium, curing the photo-curable medium by illuminating it with radiation, and removing the cured medium from the second imprint template to form a third imprint template which bears a pattern that is a substantial replica of the first pattern.