Single sequence phase shifting spectrally resolvedinterferometry for in-line thin film thicknessmeasurement using spectral reflectance and phase

The thesis aims to characterize the mechanical properties and stresses for thin films deposited on the circular substrates. First, the thin films with the same deposition condition were successively deposited on the distinct substrates using the evaporation technique. The phase-shifting Twyman-Green interferometer (PSTGI) was then employed to measure the warpage of the film-substrate structures and therefore the intrinsic stresses and thermal stresses can be calculated from the well-known Stoney’s formula. The coefficients of thermal expansion (CTE) and Young’s modulus of thin films were also obtained from the Stoney’s theory. Furthermore, the merit of full-field character of optical interferometry was used to propose a novel methodology using the Chen and Ou’s theory to improve the accuracy and to reduce the experiment procedures in the traditional measurement of the aforementioned mechanical properties. Finally, the measured results corresponding to the traditional and proposed methods were respectively substituted into their adopted theories to compare their difference. The results reveal that the accuracy of proposed methodology is considerably improved and the experimental procedures are reduced to those of the traditional methods.

Download Full-text

Spectrally resolved white–light phase–shifting interference microscopy for thickness–profile measurements of transparent thin film layers on patterned substrates

Optics Express ◽

10.1364/oe.14.004662 ◽

2006 ◽

Vol 14 (11) ◽

pp. 4662 ◽

Cited By ~ 44

Author(s):

Sanjit K. Debnath ◽

Mahendra P. Kothiyal ◽

Joanna Schmit ◽

Parameswaran Hariharan

Keyword(s):

Thin Film ◽

White Light ◽

Phase Shifting ◽

Interference Microscopy ◽

Patterned Substrates ◽

Light Phase ◽

Thickness Profile ◽

Spectrally Resolved

Download Full-text

Thin Film Reflectance Model for Trap Detector

10.51843/wsproceedings.2021.23 ◽

2021 ◽

Author(s):

Brian H.T. Lee ◽

◽

Brenda H.S. Lam ◽

C.M. Tsui

Keyword(s):

Thin Film ◽

Spectral Reflectance ◽

Internal Quantum Efficiency ◽

Oxide Thickness ◽

Thickness Variation ◽

Spectral Responsivity ◽

Silicon Photodiode ◽

Measurement Models ◽

Trap Detector ◽

Reflectance Model

The physical model of the spectral responsivity of trap detector consists of multiple parameters such as the internal quantum efficiency and the spectral reflectance. In some measurement models, the spectral reflectance of the trap detector is approximated by fitting a wavelength dependence equation which does not consider the effect of the oxide thickness of the silicon photodiode. To analyse the uncertainty due to the oxide thickness variation, a thin film reflectance model is set up in the Standards and Calibration Laboratory (SCL) for the evaluation of the spectral reflectance of the trap detectors. The model is based on the Fresnel coefficients of a 3-layer thin film structure which consists of air and a thin film oxide layer on a silicon substrate. The reflectance model was implemented as user-defined functions to calculate the spectral reflectance at different oxide thickness. It was also integrated with the SCL’s MCM program to evaluate the uncertainty of the spectral responsivity of trap detectors.

Download Full-text