Patent ID: 7541121
Filing Date: 2009-06-02
Classification: G03F

Abstract:
1. A method of calibrating line shortening measurements, the method comprising: providing a workpiece, the workpiece comprising a layer of photosensitive material disposed thereon; exposing a selected region of the layer of photosensitive material to energy through a flare sensitive first test pattern and exposing said selected region to energy through a second test pattern, said first test pattern and said second test pattern disposed on at least one mask, said second test pattern comprising an opaque or attenuated region located proximate a portion of the flare sensitive first test pattern, the flare sensitive first test pattern defining a first area having a first and a second dimension and comprising a plurality of parallel gratings arranged in one of rows and columns and each of said plurality of parallel gratings having a length the same as one of said first and second dimensions, and wherein a calibration marker is disposed within at least one of the plurality of parallel gratings; developing the layer of exposed photosensitive material; measuring features formed on the layer of photosensitive material by portions of the flare sensitive first test pattern that are proximate the second test pattern to determine a first line shortening measurement resulting at least partially because of the close proximity of said opaque or attenuated region of said second test pattern to said first test pattern; determining a second line shortening measurement using the calibration marker; and comparing the second line shortening measurement to the first line shortening measurement to determine a calibration factor for line shortening measurements.