Abstract
A three-axis automated scatterometer (TAAS) with a high accuracy goniometric table, a fiber-coupled power stabilized diode laser, and a large dynamic range detector has been constructed and characterized to measure the bidirectional reflectance distribution function (BRDF) from samples. This scatterometer is capable of both the in-plane and out-of-plane measurements. The goniometric table is comprised of three computer-controlled rotary stages of high angular resolution. The optical sources are fiber-coupled diode lasers at wavelength Λ = 405 and 660 nm, respectively. The diode lasers exhibit excellent power stability and wavelength stability. Silicon and germanium photodiode detectors are used with a lock-in amplifier. The calibration is fulfilled by measuring the reflectance from a polished silicon wafer. When the experimantal data were compared with the numerical data from the Fersnel's equations, the root-mean-square difference is 0.77%. The combined uncertainty was estimated to be less than 1% for the current and following measurements.