Patent ID: 7837907

Claim:
A method for aligning a template mold to a substrate wherein detection of the substrate uses only edges of the substrate, comprising: placing a sensor system over the template mold and the substrate, the sensor system generating a beam of optical energy and configured to receive only portions of the optical energy reflected in an angular window from the detection surfaces, wherein the sensor system generates sensor signals in response to variations in received optical energy reflected from the detection surfaces of the template mold and the substrate; positioning the template mold in response to control signals to locate the template mold in tool coordinates, wherein the template mold has an active area with imprintable features surrounded by gratings having detection surfaces at a pitch corresponding to a predetermined dimensional increment; positioning the substrate in response to control signals to locate the substrate in tool coordinates, wherein only edges of the substrate are configured as detection surfaces; processing the sensor signals in a controller to locate the template mold relative to the substrate in tool coordinates; and generating the control signals to thereby position the substrate accurately with respect to the template mold in the tool coordinates wherein the substrate is positioned on a chuck, the chuck having a first surface and the edge of the substrate having a second surface such that the first surface directs a beam substantially to the sensor system and the second surface directs a beam substantially away from the sensor system providing variations in received optical energy of the sensor system.