Radiation thermometry of silicon wafers based on emissivity-invariant condition

Abstract

An emissivity-invariant condition for a silicon wafer was determined by simulation modeling and it was confirmed experimentally. The p-polarized spectral emissivity at a wavelength of 900 nm and at temperatures over 900 K was constant at 0.83 at an angle of about 55.4° irrespective of large variations in the oxide layer thickness and the resistivity due to the different impurity doping concentrations of the silicon wafer. The expanded uncertainty, U(c) = ku(c) (k = 2), of the temperature measurement is estimated to be 4.9 K. This result is expected to significantly enhance the accuracy of radiometric temperature measurements of silicon wafers in actual manufacturing processes.

A method of reducing background radiance for emissivity-compensated radiation thermometry of silicon wafers

“…Simulation results for the ppolarized emissivity ε p (θ ) at the Brewster angle were 0.87 for SiO 2 film and 0.93 for Si 3 N 4 film, respectively. 8 The simulation results agree well with the experimental results in Fig. 2.…”

“…The two emissivity-compensated radiation thermometry methods based on polarization techniques are briefly summarized below since these methods and their experimental setups have previously been described in detail; 8,9 the reduction of the background radiance is described in more detail below because its principle and experimental setup has been only partially introduced previously. 10 Many n-type silicon (100) wafers (thickness: 0.75 mm; diameter: 76.2 mm) were prepared for experiments.…”

“…8 This method is valid for a wide range of conditions (resistivity ρ = 0.01-2000 cm, film thickness d = 30-1050 nm, temperature T = 700-850 • C, and wavelength λ = 0.9-4.8 μm).…”

“…In this study, we consider two emissivity-compensated radiation thermometry methods: an emissivity-invariant radiation thermometry method 8 and a method that simultaneously measures the emissivity and temperature based on the ratio of polarized radiance. 9 We then develop a method that greatly reduces the background radiance by separating the radiance from the wafer surface from the radiance from the lamps.…”

Environmental Radiation Change-based Emissivity Measurement Method for Field Targets

“…Infrared imaging temperature measurement has the advantages of being non-contact, highly sensitive, and fast; this approach has a wide temperature range, is capable of night vision, and has high security. Such measurement has been widely applied in the civil fields of high-voltage line inspection and industrial production, as well as in the military fields of reconnaissance and guidance, camouflage design, and detection [1][2][3]. The surface emissivity of a measured object mainly affects the thermal imager.…”