Color-imaging ellipsometer: High-speed characterization of in-plane distribution of film thickness at nano-scale

We have developed a new type of imaging ellipsometer that is capable of rap idly visualizing the in-plane distribution of film thickness at the nanomet er scale and displaying the results as a color distribution. Simultaneous u se of three different wavelengths was made possible by capture with a color charge-coupled devices video camera at an acquisition speed of 5-10 frame/ s followed by rapid image processing. This instrument has two main advantag es when compared with a monochrome-imaging ellipsometer. The first is the c apability of visualizing the difference between thin and thick areas of a f ilm in one frame of video-image. The second is the ability to calculate the in-plane distribution of film thickness from the intensities of the three wavelengths in one frame without mechanical movements of any of the optical elements of the ellipsometer. We have demonstrated the performance of this instrument by measuring the thicknesses of four different SiO2 films simul taneously prepared on one Si substrate.