Process for measuring the thickness and composition of thin semiconductor films deposited on semiconductor wafers

摘要

The invention works by taking optical reflectance measurements on the deposited layers at different wavelengths and fitting the measured results to extract the thicknesses and compositions. The process of the present invention simultaneously measures the thicknesses of elemental and binary semiconductors' layers and the thicknesses and composition of ternary layers. Highly precise thickness and composition estimates and wafer maps of the growth rates and composition are provided by (1) measuring in a wavelength range at which the index of refractions are rapidly varying and (2) growing a special high reflectance test structure consisting of alternating layers of the materials to be measured.