Patent ID: 7854867

Claim:
A method for detecting a particle between a nanoimprint mold assembly and a substrate in a nanoimprint lithography system, said method comprising: positioning said nanoimprint mold assembly and said substrate in a desired spatial relationship using an imprint head and a stage, said nanoimprint mold assembly and said substrate being spaced-apart to define a desired distance and desired volume therebetween, said distance having an expected value and said volume substantially filled by polymerizable material; measuring said distance between said nanoimprint mold assembly and said substrate employing encoder signals produced by said imprint head, defining a measured value of said distance, wherein measuring occurs after fluid has filled the volume between said nanoimprint mold assembly and said substrate; comparing said measured value of said distance with said expected value of said distance, defining a difference between said measured value and said expected value; and determining a presence of said particle between said nanoimprint mold assembly and said substrate based on said difference.