Research On Nano Film Thickness Ellipsometry Metrology Method And Device

Nanofilms combine the advantages of both traditional composite materials and modern nanomaterials,and are widely used in industries such as integrated circuits,photovoltaic cells,and liquid crystal panels.The accuracy of film thickness parameter measurement is of great importance to guarantee the performance of products.Ellipsometry measurement of micro and nano film thickness has the advantages of fast,non-destructive and high accuracy,and is now widely used.In order to realize the traceability of film thickness as a length geometric quantity,this paper studies the principle of ellipsometry measurement and derives the mathematical model between the film thickness quantity and laser wavelength,based on which a laser ellipsometry measurement device is designed and developed to realize the traceability of ellipsometry film thickness measurement to the laser wavelength length measurement reference.The main research work of this paper includes:1.The multi-beam reflection and refraction model of polarized light in ellipsometry measurements is investigated,and a direct function between the thickness of the micro-nano film and the laser wavelength is derived.2.A detailed selection and design of the optical measurement,rotation control and mounting adjustment modules of the ellipsometry system was carried out,and the laser ellipsometry measurement device was developed to realize the traceability of the ellipsometry measurement of micro and nano film thickness to the laser wavelength length measurement reference.3.The key parameters in ellipsometry measurement: measurement incidence angle,ellipsometric parameters and are simulated and analyzed,and an initial 90°azimuth calibration method for ellipsometric measurement is proposed for measurement incidence angle,which effectively improves the measurement accuracy of the device.4.The error sources of the ellipsometry measurement device were analyzed,and the parameters such as laser wavelength,film thickness refractive index and polarizer rotation angle during the measurement process were calibrated,and the measurement uncertainty evaluation of the laser ellipsometry measurement device was completed.The laser ellipsometry device repeatedly measured the 108.40 nm silica on silicon standard film thickness slice for several times,and the measurement error was less than0.3 nm,and the measurement uncertainty was 0.36 nm,which showed that the device has good measurement accuracy and repeatability.