One-shot nanoscale surface height variation measurement of a bare silicon wafer using a single reflectance direction field

It has been demonstrated that nanoscale height variations on a bare silicon wafer can be reconstructed from a single image obtained in one shot using a color mapping imaging system of a reflectance direction field. This imaging system can acquire the direction of light rays reflected from the wafer's surface as color information by utilizing a filter with a multicolor stripe pattern. A prototype of the imaging system is capable of capturing an image of a 12 × 8 mm area of the silicon wafer with a resolution of 2.18 × 2.18 µm. The height error distribution in the reconstruction from the ideal surface varies between -18% and 6%.