Working at the NIST Center for Neutron Research, chemical engineer Eric Lin places a semiconductor wafer in the path of a focused neutron beam. The beam is used to determine the size and shape of polymer patterns on the silicon wafer. Twenty-eight magnesium fluoride lenses focus the neutron beam so that the instrument can characterize polymer structures between 100-300 nanometers wide.

The graphic (left) shows the two-dimensional scattering data from a polymer grating pattern with 150 nanometer linewidths. The colors represent the intensity of the scattered neutrons on the square detector. White areas represent the highest intensity followed by red through the colors of the rainbow to black. The bright diffraction spots to either side of the center show that the sample is evenly spaced over a large area. The relative brightness of the spots is related to the average shape and roughness of the lines in the pattern.